Journal articles: 'Heat source model'

1

Mei, Viung C. "Heat Transfer of Buried Pipe for Heat Pump Application." Journal of Solar Energy Engineering 113, no. 1 (February 1, 1991): 51–55. http://dx.doi.org/10.1115/1.2929951.

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It is generally felt that the application of line source theory for ground coil design usually resulted in excessive overdesign. It was anticipated that in order for the ground coil heat pump systems to be economically competitive with other residential heating and cooling systems, ground coil overdesign had to be kept to a minimum. A new ground coil model was derived, which based on energy balance rather than the traditional line source theory. It was aimed to more accurately predict the operation of ground coils. It is the intention of this study to compare this ground coil model with models based on line source theory, a simple line source model and a modified line source model, by using them to simulate the same field test data for both summer and winter ground coil operations. The results indicated that for winter coil operation, the new model predicted the coil liquid exit temperature less than 2°C maximum deviation from the measured values, with an average deviation less than 1°C. The modified line source model had an average deviation of more than 1.5°C. For summer operation, all models underpredicted the measured soil temperatures because the effect of thermal backfill material was not included in the models. The new model still predicted the test results better than the other two models. However, when the effect of sand thermal backfill was included in the new model, which was not easy for the other two models, the calculated soil temperatures were almost identical to the test results.

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Meng, Qingguo. "HEAT SOURCE MODEL FOR TWIN WIRE WELDING." Chinese Journal of Mechanical Engineering 41, no. 04 (2005): 110. http://dx.doi.org/10.3901/jme.2005.04.110.

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Hongyuan, Fang, Meng Qingguo, Xu Wenli, and Ji Shude. "New general double ellipsoid heat source model." Science and Technology of Welding and Joining 10, no. 3 (June 2005): 361–68. http://dx.doi.org/10.1179/174329305x40705.

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Hasavimath, Kartikaswami, Kishan Naik, Banjara Kotresha, and N. Gnanasekaran. "Forced Convection through Discrete Heat Sources and Simple Thermal Model – A Numerical Study." International Journal of Mathematical, Engineering and Management Sciences 4, no. 6 (December 1, 2019): 1397–406. http://dx.doi.org/10.33889/ijmems.2019.4.6-110.

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In this work a forced convection through discrete heat sources and simple thermal model placed inside the vertical channel is analyzed numerically. The problem considered for the investigation comprises of a vertical channel with distinct heat source assembly located at the center of the channel. The novelty of the present work is to replace the discrete heat source assembly by a simple thermal model to obtain uniformly distributed temperature and streamlines. A conjugate heat transfer investigation is carried out because the problem domain consists of aluminum solid strips as well as Bakelite strips in discrete heat source assembly which are replaced by a aluminum solid in case of simple thermal model. The numerically obtained data are initially compared with experimental data for the purpose of validation. The temperature of each discrete sources decrease with increase in inlet velocity of the fluid and bottom heat source is able to take higher heat load. The results in terms excess temperature obtained for both discrete heat source and simple thermal model is presented and discussed.

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Hou, Zhen-Bing, and R. Komanduri. "Magnetic Field Assisted Finishing of Ceramics—Part I: Thermal Model." Journal of Tribology 120, no. 4 (October 1, 1998): 645–51. http://dx.doi.org/10.1115/1.2833761.

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A thermal model for magnetic field assisted polishing of ceramic balls/rollers is presented. The heat source at the area of contact between the balls and the abrasives where material removal takes place is approximated to a disk. The disk heat source is considered as a combination of a series of concentric circular ring heat sources with different radii. Each ring in turn is considered as a combination of a series of infinitely small arc segments and each arc segment as a point heat source. Jaeger’s classical moving heat source theory (Jaeger, 1942; Carslaw and Jaeger, 1959) is used in the development of the model, starting from an instantaneous point heat source, to obtain the general solution (transient and steady-state) of the moving circular ring heat source problem and finally the moving disc heat source problem. Due to the formation of fine scratches during polishing (on the order of a few micrometers long), the conditions are found to be largely transient in nature. Calculation of the minimum flash temperatures and minimum flash times during polishing enables the determination if adequate temperatures can be generated for chemo-mechanical polishing or not. This model is applied in Part II for magnetic float polishing (MFP) of ceramic balls and in Part III for magnetic abrasive finishing (MAF) of ceramic rollers.

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Ma, Bao Ji, Yu Quan Zhu, and Xiao Li Jin. "Heat Source and Heat Partition Models in ELID Grinding." Advanced Materials Research 328-330 (September 2011): 115–19. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.115.

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Based on the feature of the ELID grinding, heat production mechanism in the ELID grinding was analyzed and a heat source model was given. Heat partition among work-piece, grinding wheel and electrolyte was discussed and a heat partition model was established. And numerical investigation was down. The results indicated that heat in ELID grinding was mainly produced by interaction between grit and work piece. Partition of the heat among work piece, grinding wheel and electrolyte was function of position. Electrolyte and grinding wheel take away the most heat produced in ELID grinding.

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He, Zeqing, Yingli Shi, Yuqing Shen, Zhigang Shen, Taihua Zhang, and Zhao Zhao. "Transient Heat Conduction in the Orthotropic Model with Rectangular Heat Source." Micromachines 13, no. 8 (August 16, 2022): 1324. http://dx.doi.org/10.3390/mi13081324.

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Epidermal electronic systems (EESs) are a representative achievement for utilizing the full advantages of ultra-thin, stretchable and conformal attachment of flexible electronics, and are extremely suitable for integration with human physiological systems, especially in medical hyperthermia. The stretchable heater with stable electrical characteristics and a uniform temperature field is an irreplaceable core component. The inorganic stretchable heater has the advantage of maintaining stable electrical characteristics under tensile deformation. However, the space between the patterned electrodes that provides tensile properties causes uneven distribution of the temperature field. Aiming at improving the temperature distribution uniformity of stretchable thermotherapy electrodes, an orthotropic heat transfer substrate for stretchable heaters is proposed in this paper. An analytical model for transient heat conduction of stretchable rectangular heaters based on orthotropic transfer characteristics is established, which is validated by finite element analysis (FEA). The homogenization effect of orthotropic heat transfer characteristics on temperature distribution and its evolutionary relationship with time are investigated based on this model. This study will provide beneficial help for the temperature distribution homogenization design of stretchable heaters and the exploration of its transient heat transfer mechanism.

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Tongov, Manahil. "HEAT SOURCE FOR TIG WELDING MODELLING." ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 3 (June 16, 2021): 348–56. http://dx.doi.org/10.17770/etr2021vol3.6601.

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A new model of heat source applicable to TIG welding is proposed. The model uses three calibration parameters - efficiency, effective heating spot radius and heat source concentration factor. Based on the experimental results, the model was calibrated and the results obtained for the form of penetration were compared with the experimental ones.

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9

Chen, Yanbin. "Model of laser-TIG hybrid welding heat source." Chinese Journal of Mechanical Engineering (English Edition) 17, no. 04 (2004): 511. http://dx.doi.org/10.3901/cjme.2004.04.511.

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10

Zhang, Chao, Xiao Dan Zhao, and Guang Hui Zhou. "The Numerical Simulation of the Solar-Air Dual-Source Heat Pump System." Applied Mechanics and Materials 138-139 (November 2011): 305–9. http://dx.doi.org/10.4028/www.scientific.net/amm.138-139.305.

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The heat pump technology which is as an effective energy-saving technology has attracted more and more attentions. A novel solar-air dual-source heat pump system which could synchronously use two heat sources has been provided. In this paper, the mathematical model of the new heat pump system has been built and the calculation accuracy of the mathematical model has been proved. Based on a novel solar-air dual-source heat pump system, the mathematical models of the thermophysical parameters of working fluids, compressor, capillary, condenser, evaporator, and heat pump system have been established. The distribution parameter method has been adopted in the mathematical models of condenser and evaporator. Three operation modes of the novel solar-air dual-source heat pump system have been simulated. The simulated results and the experimental results have been compared. The experiments of the novel solar-air dual-source heat pump system have been accomplished in the constant temperature and humidity laboratory. The compared results show that the error is less than 10%.

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11

Kik, Tomasz. "Heat Source Models in Numerical Simulations of Laser Welding." Materials 13, no. 11 (June 10, 2020): 2653. http://dx.doi.org/10.3390/ma13112653.

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The article presents new possibilities for modifying heat source models in numerical simulations of laser welding processes conducted using VisualWeld (SYSWELD) software. Due to the different power distributions and shapes of a laser beams, it was necessary to propose a modification of heat source models and methods of defining the heat introduced into a welded material in the case of simulations of welding processes using solid-state and high-power diode lasers. A solution was proposed in the form of modification of predefined heat source models in the case of simulations of welding processes using solid-state disc lasers and high-power diode lasers (HPDL). Based on the results of metallographic tests and the acquisition of thermal cycles of real laser welding processes, the process of calibration and validation of the proposed models of heat sources depending on the type of device used as well as the obtained shapes of fusion beads was carried out. The purpose and assumptions of this approach towards creating heat sources were also reported, comparing exemplary stresses and cumulative plastic strain distributions for the calculation variant using a standard and modified heat source model.

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Alexeev, Anton, Grigory Onushkin, Jean-Paul Linnartz, and Genevieve Martin. "Multiple Heat Source Thermal Modeling and Transient Analysis of LEDs." Energies 12, no. 10 (May 15, 2019): 1860. http://dx.doi.org/10.3390/en12101860.

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Thermal transient testing is widely used for LED characterization, derivation of compact models, and calibration of 3D finite element models. The traditional analysis of transient thermal measurements yields a thermal model for a single heat source. However, it appears that secondary heat sources are typically present in LED packages and significantly limit the model’s precision. In this paper, we reveal inaccuracies of thermal transient measurements interpretation associated with the secondary heat sources related to the light trapped in an optical encapsulant and phosphor light conversion losses. We show that both have a significant impact on the transient response for mid-power LED packages. We present a novel methodology of a derivation and calibration of thermal models for LEDs with multiple heat sources. It can be applied not only to monochromatic LEDs but particularly also to LEDs with phosphor light conversion. The methodology enables a separate characterization of the primary pn junction thermal power source and the secondary heat sources in an LED package.

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13

Zhan, Xiaohong, Qi Zhang, Qibing Wang, Jie Chen, Hongbing Liu, and Yanhong Wei. "Numerical simulation of flow field in the Invar alloy laser–MIG hybrid welding pool based on different heat source models." International Journal of Numerical Methods for Heat & Fluid Flow 28, no. 4 (April 3, 2018): 909–26. http://dx.doi.org/10.1108/hff-02-2017-0069.

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Purpose The purpose of this paper is to establish a three-dimensional flow field model of the Invar alloy laser–metal inert gas (laser–MIG) hybrid welding process to investigate the influence of different heat sources between different layers and to analyze the flow field based on the two different heat source models for the multilayer welding. Design/methodology/approach The Invar steel plates with 19.5 mm thickness are welded into three layers’ seam using the hybrid laser–MIG welding technology. The flow field based on different heat source models is studied and then used to investigate the influence of different heat sources in different layers during the laser–MIG hybrid welding process. The simulation results of flow field using two different heat source models are compared with experiments. Findings The flow field simulations results show that using the Gaussian rotating body heat source model to simulate the temperature field is more consistent with the experiment of the hybrid laser–MIG welding where its flow field between different layers better reflects the characteristics of the hybrid laser–MIG welding. Originality/value The findings will be useful in the study of a variety of thick-plate laser–MIG hybrid welding process fluid flows.

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14

Dhinakaran, V., N. Siva Shanmugam, and K. Sankaranarayanasamy. "Some studies on temperature field during plasma arc welding of thin titanium alloy sheets using parabolic Gaussian heat source model." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, no. 4 (August 8, 2016): 695–711. http://dx.doi.org/10.1177/0954406215623574.

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In this paper, a new volumetric heat source model is developed for predicting the weld bead geometry during plasma arc welding of thin sheets of titanium alloy. Numerical simulations are carried out with the proposed parabolic Gaussian heat source (PGHS) model and already prevailing familiar heat source models namely, conical heat source and modified conical heat source, using finite element package COMSOL. The temperature-dependent material properties for Ti–6Al–4V alloy are considered for performing numerical calculations, which tend to influence the temperature fields while computing. Besides, the effect of trailing gas shielding, latent heat, and radiative and convective heat transfer are taken into account while performing the transient thermal analysis which significantly alters the sensitivity and accuracy of the model. Experimental trials on thin titanium alloy sheets are carried out to enable the validation of the proposed PGHS model. Subsequently, the outcome reveals that the PGHS model is capable and proved its high degree of efficiency in predicting the weld bead geometry more accurately than the existing heat source models. The distribution of heat intensity along the thickness of thin sheet is observed to be parabolic as predicted by the proposed model. The prediction appears to have a good correlation with the experimental result and it is clearly perceptible that the parabolic shape is more reliable and yields greater accuracy of the proposed heat source model.

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15

Fawad, Hasan. "Heat Transfer Modeling of Metal Deposition Employing Welding Heat Source." Applied Mechanics and Materials 315 (April 2013): 463–67. http://dx.doi.org/10.4028/www.scientific.net/amm.315.463.

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Gas Metal Arc welding (GMAW) has shown potential, for Layered Manufacturing (LM) of metallic components, due to its inherent feature of high inter-layer and metallurgical bonding. Residual Stress induced warping is a major concern in a variety of LM processes, particularly those seeking to build parts directly without post processing steps. The temperature distribution and re-melting depth plays an important role in controlling residual stresses and distortion. This paper presents a 3D finite element based thermal model of a novel welding based deposition process as applied to LM. The model showed good agreement with experimental data. The results show that the process is not axis symmetric and a complete 3D model is required for accurate prediction of temperatures and deformation.

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Ciapała, Jurasz, and Kies. "The Potential of Wind Power-Supported Geothermal District Heating Systems—Model Results for a Location in Warsaw (Poland)." Energies 12, no. 19 (September 27, 2019): 3706. http://dx.doi.org/10.3390/en12193706.

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Geothermal heat is considered a sustainable energy source with significant global potential. Together with heat distribution networks, it can provide clean thermal energy to individual and commercial consumers. However, peaks in heat demand can require additional peaking sources at times. In this paper, we investigated how wind turbines can act as a peak energy source for a geothermal district heating system. We studied a model consisting of a geothermal heat source, a heat storage and wind power generator using historical weather data of Warsaw (Poland) and showed that wind power could increase the renewable share to supply a considerable heat demand compared to a geothermal heat source alone. The results indicate that wind power can be a suitable complement for a geothermal heat source to provide energy for heating. It is shown that a theoretical geo-wind-thermal storage based district heating network supplying 1000 m2, which requires 100 W/m2 at an outdoor temperature of −20 °C should have the following parameters: 4.8 MWh of thermal energy storage capacity, 45 kW of geothermal capacity and 5 kW of wind capacity. Such a system would ensure minimal wind curtailment, high utilization of geothermal source and high reliability of supply.

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Hu, Changming, Rui Wang, Ping Yang, Weihao Ling, Min Zeng, Jiyu Qian, and Qiuwang Wang. "Numerical Investigation on Two-Phase Flow Heat Transfer Performance and Instability with Discrete Heat Sources in Parallel Channels." Energies 14, no. 15 (July 21, 2021): 4408. http://dx.doi.org/10.3390/en14154408.

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With the rapid development of integrated circuit technology, the heat flux of electronic chips has been sharply improved. Therefore, heat dissipation becomes the key technology for the safety and reliability of the electronic equipment. In addition, the electronic chips are distributed discretely and used periodically in most applications. Based these problems, the characteristics of the heat transfer performance of flow boiling in parallel channels with discrete heat source distribution are investigated by a VOF model. Meanwhile, the two-phase flow instability in parallel channels with discrete heat source distribution is analyzed based on a one-dimensional homogeneous model. The results indicate that the two-phase flow pattern in discrete heat source distribution is more complicated than that in continuous heat source distribution. It is necessary to optimize the relative position of the discrete heat sources, which will affect the heat transfer performance. In addition, compared with the continuous heat source, the flow stability of discrete heat sources is better with higher and lower inlet subcooling. With a constant sum of heating power, the greater the heating power near the outlet, the better the flow stability.

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Kiran, Abhilash, Ying Li, Josef Hodek, Michal Brázda, Miroslav Urbánek, and Jan Džugan. "Heat Source Modeling and Residual Stress Analysis for Metal Directed Energy Deposition Additive Manufacturing." Materials 15, no. 7 (March 30, 2022): 2545. http://dx.doi.org/10.3390/ma15072545.

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The advancement in additive manufacturing encourages the development of simplified tools for deep and swift research of the technology. Several approaches were developed to reduce the complexity of multi-track modeling for additive manufacturing. In the present work, a simple heat source model called concentrated heat source was evaluated for single- and multi-track deposition for directed energy deposition. The concentrated heat source model was compared with the widely accepted Goldak heat source model. The concentrated heat source does not require melt pool dimension measurement for thermal model simulation. Thus, it reduces the considerable time for preprocessing. The shape of the melt pool and temperature contour around the heat source was analyzed for single-track deposition. A good agreement was noticed for the concentrated heat source model melt pool, with an experimentally determined melt pool, using an optical microscope. Two heat source models were applied to multi-track 3D solid structure thermo-mechanical simulation. The results of the two models, for thermal history and residual stress, were compared with experimentally determined data. A good agreement was found for both models. The concentrated heat source model reported less than the half the computational time required for the Goldak model. The validated model, for 3D solid structure thermo-mechanical simulation, was used to analyze thermal stress evolution during the deposition process. The material deposition on the base plate at room temperature results in lower peak temperatures in the layers near the base plate. Consequently, the higher thermal stress in the layers near the base plate was found, compared to the upper layers during the deposition process.

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Huang, Y., and S. Y. Liang. "Modelling of the cutting temperature distribution under the tool flank wear effect." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 217, no. 11 (November 1, 2003): 1195–208. http://dx.doi.org/10.1243/095440603771665232.

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The understanding of cutting temperature distribution at the presence of tool wear can aid in addressing important metal cutting issues such as part surface integrity, tool life and dimensional tolerance under practical operating conditions. The effect of tool wear on the cutting temperature distribution was first modelled by Chao and Trigger and there have been very few followers since. In Chao's model, the primary heat source was assumed to have no effect on the workpiece temperature rise and the chip temperature rise was treated as a bulk quantity. This paper analytically quantifies the tool wear effect by taking into account the contributions of the primary heat source and considering the distribution of chip temperature rise. On the chip side, the primary shear zone is modelled as a uniform moving oblique band heat source and the secondary shear zone as a non-uniform moving band heat source within a semi-infinite medium. On the tool side, the effects of both the secondary and the rubbing heat sources are modelled as non-uniform static rectangular heat sources within a semi-infinite medium. For the workpiece side, the study models the primary shear zone as a uniform moving oblique band heat source and the rubbing heat source as a non-uniform moving band heat source within a semi-infinite medium. The proposed model is verified based on the published experimental data in the orthogonal cutting of Armco iron. Furthermore, a comparison case is presented on the temperature variation with respect to cutting speed, feed rate and flank wear length.

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Li, Kuan-Ming, and Steven Y. Liang. "Modeling of Cutting Temperature in Near Dry Machining." Journal of Manufacturing Science and Engineering 128, no. 2 (October 13, 2005): 416–24. http://dx.doi.org/10.1115/1.2162907.

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Near dry machining refers to the condition of applying cutting fluid at relatively low flow rates, on the order of 2-100ml∕h, as opposed to the conventional way of using either a large quantity, typically of about 10l∕min, as in wet machining; or no fluid at all, as in dry machining. One important expectation of applying fluids is to control the cutting temperature, which is an important parameter for tool life and part dimensional accuracy in machining processes. In this context, the understanding of cutting temperature variation corresponding to the near dry cooling and lubrication is of interest. This paper models the temperature distributions in the cutting zone under through-the-tool near dry cooling condition. The heat source method is implemented to estimate the cutting temperatures on the tool-chip interface and the tool-workpiece interface. For the temperature rise in the chip, the effects of the primary heat source and the secondary heat source were modeled as moving heat sources. For the temperature rise in the tool, the effects of the secondary heat source, the heat loss due to cooling, and the rubbing heat source due to the tool flank wear, were modeled as stationary heat sources. For the temperature rise in the workpiece, the primary heat source, the heat loss due to cooling, and the rubbing heat source due to the tool flank wear were modeled as moving heat sources. The model describes the dual effects of air-oil mixture in near dry machining in terms of the reduction of cutting temperature through the cooling effect, as well as the reduction of heat generation through the lubricating effect. To pursue model calibration and validation, embedded thermocouple temperature measurement in cutting medium carbon steels with uncoated carbide insets were carried out. The model predictions and experimental measurements show reasonable agreement and results suggest that the combination of the cooling and the lubricating effects in near dry machining reduces the cutting temperatures on the tool-chip interface by about 8% with respect to dry machining. Moreover, the cutting speed remains a dominant factor in cutting temperature compared with the feed and the depth of cut in near dry machining processes.

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Trimmel, Heidelinde, Clement Gangneux, Gerda Kalny, and Philipp Weihs. "Application of the model ‘Heat Source’ to assess the influence of meteorological components on stream temperature and simulation accuracy under heat wave conditions." Meteorologische Zeitschrift 25, no. 4 (September 6, 2016): 389–406. http://dx.doi.org/10.1127/metz/2016/0695.

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Zhang, Jian Hua, Xiao Jun Zhang, Guo Ying Yu, Mei Lin Gu, and Pei Qi Ge. "An Investigation on the Heat Partitioning in Grind-Hardening." Advanced Materials Research 97-101 (March 2010): 2095–98. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.2095.

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The heat partitioning to workpiece is an important parameter, which affects the grind-hardening technology. In this paper, the heat sources positions, which are around the grain, are analyzed. Ignoring the heat source produced in chip-grain interface, the heat partition model is established based on heat source position produced in grain-workpiece interface and the chip-workpiece interface. The heat partition is validated by using of finite element method and the experimental method. The results indicate the heat partition model can be used in grind-hardening temperature calculation.

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KAMEI, Yuki, Hideo UTSUNO, and Jyunichi KURATA. "Acoustic Model Generation of Heat Source in Rijke Tube." Proceedings of the Dynamics & Design Conference 2020 (August 25, 2020): 605. http://dx.doi.org/10.1299/jsmedmc.2020.605.

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Cai, Zhipeng. "MODEL OF STRING HEAT SOURCE IN WELDING NUMERICAL SIMULATIONS." Chinese Journal of Mechanical Engineering 37, no. 04 (2001): 25. http://dx.doi.org/10.3901/jme.2001.04.025.

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Abdelaziz, Sherif L., Tolga Y. Ozudogru, C. Guney Olgun, and James R. Martin. "Multilayer finite line source model for vertical heat exchangers." Geothermics 51 (July 2014): 406–16. http://dx.doi.org/10.1016/j.geothermics.2014.03.004.

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Shen, Bo, Joshua New, and Van Baxter. "Air source integrated heat pump simulation model for EnergyPlus." Energy and Buildings 156 (December 2017): 197–206. http://dx.doi.org/10.1016/j.enbuild.2017.09.064.

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Ma, Zhenjun, and Lei Xia. "Model-based Optimization of Ground Source Heat Pump Systems." Energy Procedia 111 (March 2017): 12–20. http://dx.doi.org/10.1016/j.egypro.2017.03.003.

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Yang, Lian, Yong Hong Huang, and Liu Zhang. "Study on Engineering Construction with Three-Dimensional Heat Transfer Modeling for Double U-Tube Heat Exchangers in Ground-Source Heat Pump Systems." Advanced Materials Research 700 (May 2013): 231–34. http://dx.doi.org/10.4028/www.scientific.net/amr.700.231.

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There are many ground source heat pumps in engineering construction application. However, Research on heat exchanger models of single-hole buried vertical ground source heat pump mostly focuses on single U-tube ground heat exchangers other than double U-tube ones in China currently. Compared with single U-tubes, double U-tubes have the heat transfer particularity of asymmetry. Therefore, the use of the traditional single tube models would have large error in the simulation of the actual double U-tube heat exchangers. This paper frames a three-dimensional heat transfer model for the vertical single-hole buried double u-tube heat exchanger in a ground source heat pump system. The model considers the performance of U-bube material and uses a dual coordinate system and makes the control elemental volumes superimposed.

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Li, Peisheng, Xiaolong Lian, Yue Chen, Ying Zhang, Wandong Zhao, and Chunyang Ma. "Multiple-relaxation-time lattice Boltzmann simulation of natural convection with multiple heat sources in a rectangular cavity." Canadian Journal of Physics 98, no. 4 (April 2020): 332–43. http://dx.doi.org/10.1139/cjp-2019-0055.

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Natural convection and heat transfer in a square cavity with multiple heat sources was investigated through a multiple-relaxation-time (MRT) collision model and lattice Boltzmann method (LBM) in the current work. The MRT-LBM model was verified by a former experiment and numerical findings with different Ra numbers from 103 to 105, which proved the MRT-LBM model is effective to handle the flow and transfer. The heat transfer that developed inside the cavity was analyzed under different width, height, and lateral offset of heat source in this paper. Moreover, the change of spacing between two symmetrically distributed heat sources was discussed. The results showed that the heat exchange efficiency was augmented by increasing width, height, and spacing of the heater, but it was reduced by increasing lateral offset. Specifically, the Nusselt number of the upper wall decreased by increasing height of heat source, and the left and right walls showed better heat exchange efficiency by increasing height. Additionally, the lateral position had a notable influence on the left wall surface of the heat source, and the optimum heat exchange efficiency of the heat source’s left wall existed in the condition of small lateral offset.

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Guo, Kai, Yunping Ji, Yiming Li, Xueliang Kang, Huiyi Bai, and Huiping Ren. "Numerical Simulation of Temperature Field and Melt Pool Characteristics of CP-Ti Manufactured by Laser Powder Bed Fusion." Metals 13, no. 1 (December 20, 2022): 11. http://dx.doi.org/10.3390/met13010011.

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A coupled heat source model that combined a Gauss surface heat source with a Gauss cylindrical volumetric heat source was introduced to simulate temperature field distribution and melt pool characteristics using a finite element simulation (FEM) method for the deep and narrow melt pools formed in laser powder bed fusion (L-PBF) aiming at commercial pure titanium (CP-Ti). For comparison, the same simulations using the Gauss surface heat source model and the double ellipsoid heat source model were also performed. The simulated melt pool geometries using the coupled heat source model match well with the measurements, with an average error of 1% for the melt pool depth and 7% for the width. Based on the single-track experimental results, it was found by comparing the simulated results from the three heat source models that the coupled heat source model had better accuracy than the other two. Then, the temperature field and the melt pool geometries of CP-Ti fabricated at different laser power levels from 300 W to 500 W and scanning speeds from 600 mm/s to 4000 mm/s were simulated. According to the simulated maximum temperature and geometries of the melt pool, a suitable process parameters map for CP-Ti was obtained. The reported experimental results agree well with the simulated map. The coupled heat source model is more accurate and applicable for the deep and narrow melt pools formed during L-PBF.

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Hou, Zhong Lin, Tan Zhao, Zhen Xu, Long Hao Zhu, Jian Hua Sun, Yao Hui Jin, and Xin Ze Lv. "The New Heat Source Model of AZ31B Magnesium Alloy Laser-TIG Hybrid Welding." Key Engineering Materials 815 (August 2019): 120–24. http://dx.doi.org/10.4028/www.scientific.net/kem.815.120.

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A new heat source model consisted of inverted conical heat source and rotary Gauss body heat source is established using the CAE software for the keyhole effect of laser-TIG hybrid welding. The inverted conical heat source is used for analyzing the wide upper part of weld pool due to the rapid heat up by the laser and arc. The rotary Gauss body heat source model is used for analyzing the long and narrow lower part of weld pool formed by the laser. The result showed that, compared with other single source mode, this new heat source model may get a better simulation of the weld pool morphology, especially the inflection point near the keyhole. It provides a new method to predict the morphology and size of the weld pool of magnesium alloy laser-TIG welding.

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Yang, Xiaochuan, Ali Turan, and Shenghui Lei. "Thermoacoustic Instability in a Rijke Tube with a Distributed Heat Source." Journal of Thermodynamics 2015 (October 27, 2015): 1–9. http://dx.doi.org/10.1155/2015/949384.

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A Rijke tube with a distributed heat source is investigated. Driven by the widely existing thermoacoustic instability in lean premixed gas turbine combustors, this work aims to explore the physicochemical underpinning and assist in the elucidation and analysis of this problem. The heat release model consists of a row of distributed heat sources with individual heat release rates. The integrated heat release rate is then coupled with the acoustic perturbation for thermoacoustic analysis. A continuation approach is employed to conduct the bifurcation analysis and capture the nonlinear behaviour inherent in the system. Unlike the conventional approach by the Galerkin method, the acoustic equations are originally discretized using the Method of Lines (MOL) to build up a dynamic system. The model is first validated and shown to yield good predictions with available experimental data. Influences of multiple heat sources, time delay, and heat release distribution are then studied to reveal the extensive nonlinear characteristics involved in the case of a distributed heat source. It is found that distributed heat source plays an important role in determining the stability of a thermoacoustic system.

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Kim, Hongkyo, Yujin Nam, Sangmu Bae, and Soolyeon Cho. "Study on the Performance of Multiple Sources and Multiple Uses Heat Pump System in Three Different Cities." Energies 13, no. 19 (October 6, 2020): 5211. http://dx.doi.org/10.3390/en13195211.

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Various efforts have been made worldwide to reduce energy use for heating, ventilation, and air-conditioning (HVAC) systems and lower carbon dioxide (CO2) emissions. Research and development are essential to ensuring the efficient use of renewable energy systems. This study proposes a multiple sources and multiple uses heat pump (MMHP) system that can efficiently respond to heating, cooling, and domestic hot water (DHW) loads using multiple natural heat sources. The MMHP system uses ground and air heat as its primary heat sources and solar heat for heat storage operations and ground temperature recovery. For the efficient use of each heat source, it also determines the heat source required for operation by comparing the heat source temperatures in the same time zone. A model for predicting the heat source temperatures, electricity use, and coefficient of performance (COP) was constructed through simulation. To analyze the efficiency of the proposed system by comparing the existing air source heat pump with ground source heat pump systems, a performance analysis was conducted by setting regional and system configurations as case conditions. The results demonstrate that the electricity use of the MMHP system was 13–19% and 1–3% lower than those of air source heat pump (ASHP) and ground source (GSHP) systems, respectively. In addition, the MMHP system was the most favorable in regions with a low heating load.

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Szász, Cs. "Air-source heat pump LabView-based model development for NZEB applications." International Review of Applied Sciences and Engineering 5, no. 1 (June 1, 2014): 59–66. http://dx.doi.org/10.1556/irase.5.2014.1.8.

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Abstract A net zero-energy building (NZEB) is considered as a resident or commercial building where the energy needs are covered by using locally available renewable energy sources and technologies. Various types of heat pumps are widely used energy conversion systems for NZEB strategies implementation. This paper is focused on the development of a novel LabView-based model for an air-source heat pump system that absorbs heat from outside air and releases it inside the building as domestic hot water supply or room's space heating by using hot water-filled fan-coils. In the first research steps the mathematical background of the considered heat pump system has been developed. Then the LabView-based software implementation of the air-source heat pump and entire heating circuit model is unfolded and presented. The result is a versatile and powerful graphical software toolkit, suitable to simulate the complex heating, ventilation and air-conditioning processes in net-zero energy buildings and to perform energy balance performance evaluations. Beside the elaborated mathematical models, a concrete software implementation example and measurement data is provided in the paper. Last but not least, the proposed original model offers a feasible solution for future developments and research in NZEB applications modeling and simulation purposes.

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OKADA, Akira, Takayoshi KASUGAI, and Kazuo HIRAOKA. "Heat source model in arc welding and evaluation of weld heat-affected zone." Transactions of the Iron and Steel Institute of Japan 28, no. 10 (1988): 876–82. http://dx.doi.org/10.2355/isijinternational1966.28.876.

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Pafcuga, Marian, Michal Holubcik, Peter Durcansky, Andrej Kapjor, and Milan Malcho. "Small Heat Source Used for Combustion of Wheat-Straw Pellets." Applied Sciences 11, no. 11 (June 4, 2021): 5239. http://dx.doi.org/10.3390/app11115239.

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Wheat straw, as a secondary waste agricultural product, presents a potential renewable source of energy. It is necessary to design simple heat sources to achieve better usage. As part of an analysis of heat sources, a tubular type of heat exchanger was reviewed. The design of the exchanger was focused on the smallest possible dimensional requirements, low costs, high reliability and easy maintenance. We chose a tubular type of heat exchanger. In our case, flue gas flows through the tubes, and water flows outside of the tubes. This type of exchanger allows for continuous cleaning, but also simple maintenance, even in case of equipment failure. It is possible to replace individual parts (pipes) of equipment that are exposed to the adverse corrosive effects of biomass flue gases. A mathematical model was composed to compute the construction of a heat source. The model was verified by CFD simulation. The main idea of this design is modularity. The composed model can be used to design a series of similar heat sources with different levels of power, and which, as it is of maximal availability for this type of construction, increase use of waste straw as fuel by small farms.

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Jokisch, Torsten, Nikolay Doynov, Ralf Ossenbrink, and Vesselin Georgiev Michailov. "Heat source model for electron beam welding of nickel-based superalloys." Materials Testing 63, no. 1 (January 1, 2021): 17–28. http://dx.doi.org/10.1515/mt-2020-0002.

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Abstract An adapted heat source model is developed for transient thermal numerical analysis of electron beam welded nickel-based alloy with increased susceptibility to hot cracking. The model enables the consideration of heat redistribution due to beam deflection phenomena. The modeling concept is validated by the appropriate theoretical models and in addition, experimental studies especially performed for this purpose. Special attention is given to the calibration of heat source model parameters. The calibration procedure is based on a statistical approach involving a combination of novel analytical solutions and quasi-steady state finite element models. The model parameter field is statistically analyzed, and a prediction algorithm is developed using optimization algorithms from the six sigma theory. The reliability and practicability of the model is demonstrated by validation weldments. The work is dedicated to precisely calculating the temperature field in the high temperature region around the weld pool and thus to provide a more detailed explanation of the formation of hot cracks when welding turbine materials commonly used in industry and aircraft constructions.

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Mirkoohi, Elham, Daniel E. Seivers, Hamid Garmestani, and Steven Y. Liang. "Heat Source Modeling in Selective Laser Melting." Materials 12, no. 13 (June 26, 2019): 2052. http://dx.doi.org/10.3390/ma12132052.

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Selective laser melting (SLM) is an emerging additive manufacturing (AM) technology for metals. Intricate three-dimensional parts can be generated from the powder bed by selectively melting the desired location of the powders. The process is repeated for each layer until the part is built. The necessary heat is provided by a laser. Temperature magnitude and history during SLM directly determine the molten pool dimensions, thermal stress, residual stress, balling effect, and dimensional accuracy. Laser-matter interaction is a crucial physical phenomenon in the SLM process. In this paper, five different heat source models are introduced to predict the three-dimensional temperature field analytically. These models are known as steady state moving point heat source, transient moving point heat source, semi-elliptical moving heat source, double elliptical moving heat source, and uniform moving heat source. The analytical temperature model for all of the heat source models is solved using three-dimensional differential equations of heat conduction with different approaches. The steady state and transient moving heat source are solved using a separation of variables approach. However, the rest of the models are solved by employing Green’s functions. Due to the high temperature in the presence of the laser, the temperature gradient is usually high which has a substantial impact on thermal material properties. Consequently, the temperature field is predicted by considering the temperature sensitivity thermal material properties. Moreover, due to the repeated heating and cooling, the part usually undergoes several melting and solidification cycles, and this physical phenomenon is considered by modifying the heat capacity using latent heat of melting. Furthermore, the multi-layer aspect of the metal AM process is considered by incorporating the temperature history from the previous layer since the interaction of the layers have an impact on heat transfer mechanisms. The proposed temperature field models based on different heat source approaches are validated using experimental measurement of melt pool geometry from independent experimentations. A detailed explanation of the comparison of models is also provided. Moreover, the effect of process parameters on the balling effect is also discussed.

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Mohd. Herzwan Hamzah and Azri Alias. "Heat Generation Inside Turbocharger Without External Heat Source." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 100, no. 2 (December 31, 2022): 47–59. http://dx.doi.org/10.37934/arfmts.100.2.4759.

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Recently, many vehicle manufacturers started to invest in new technology to reduce the emission produced by their engines. Due to the emission regulations that become more stringent and the rising demand for highly efficient vehicles, many new technologies were introduced to achieve the demand. One of the technologies that gain popularity in modern vehicles is applying force induction systems such as turbocharging and supercharging the engine. By using the turbocharger, two major advantages can be achieved which are increasing engine efficiency and engine size reduction. However, turbocharger performance will be affected by the amount of heat that is generated due to friction inside the bearing, air compression process and also the heat transfer from the exhaust gas that has high temperature and pressure. In this paper, the heat generation inside the turbocharger unit without any external heat source was measured and analysed. A turbocharger unit from Garrett Turbocharger where the model is GT2056 was used for this experiment. The operating speed in the study is recorded between 20 000 rpm until 70 000 rpm and the temperature at the turbine inlet and compressor inlet is at room temperature. The parameters that were measured are the temperature difference at the turbine side, bearing housing and also compressor side. From the results obtained, it can be concluded that the bearing housing produces a higher amount of heat compared to the compressor side while the turbine side will experience heat loss.

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Ran, Chun Yu, and Li Yun Zhang. "Ground Source Heat Pump and Conventional Heat Sources to Match the Design and Operation Mode for Energy Saving." Advanced Materials Research 648 (January 2013): 189–93. http://dx.doi.org/10.4028/www.scientific.net/amr.648.189.

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According to China's current energy present situation, the use of renewable energy, saving energy and reducing consumption has become the energy industry development should follow the basic principles. Electric boiler-ground source heat pump system as one kind of building energy saving technology, mainly in soil source heat pump renewable energy utilization. In this paper the boilers and soil source heat pump matching design and operation model research, from energy efficiency, economic and technical analysis, environmental benefit analysis into consideration, and concludes that the electric boiler-ground source heat pump system has the obvious energy saving and environmental benefits.

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Hadim, H. A., and A. Bethancourt. "Numerical Study of Forced Convection in a Partially Porous Channel With Discrete Heat Sources." Journal of Electronic Packaging 117, no. 1 (March 1, 1995): 46–51. http://dx.doi.org/10.1115/1.2792066.

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A numerical study was performed to analyze steady laminar forced convection in a channel partially filled with a fluid-saturated porous medium and containing discrete heat sources on the bottom wall. Hydrodynamic and heat transfer results are reported for the configuration in which the porous layers are located above the heat sources while the rest of the channel is nonporous. The flow in the porous medium was modeled using the Brinkman-Forchheimer extended Darcy model. Parametric studies were conducted to evaluate the effects of variable heat source spacing and heat source width on heat transfer enhancement and pressure drop in the channel. The results indicate that when the heat source spacing was increased within the range considered, there was a negligible change in heat transfer enhancement while the pressure drop decreased significantly. When the heat source width was decreased, there was a moderate increase in heat transfer enhancement and a significant decrease in pressure drop.

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Ayoola, W. A., W. J. Suder, and S. W. Williams. "Comparison of Theoretical Disc and Point Source Profiles with Actual-Melt Source Profile in Conduction Welding." Nigerian Journal of Technological Development 19, no. 3 (September 23, 2022): 260–65. http://dx.doi.org/10.4314/njtd.v19i3.8.

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Prediction of fusion zone in numerical modelling of welds using a modified heat transfer model requires experimental results for validation. Primarily, the modified heat transfer models are developed from the point and disc source heat models which can be assumed to be a semi-circle or spherical shape. In this study, a simple relationship between melt areas, the depth of penetration and weld width was proposed for point and disc source profiles to represent the actual weld profile. The results obtained for focused and defocused laser beams indicate that the actual weld profile is closer to a point source than the disc source. The transition between the conduction and keyhole regimes was achieved when the actual weld depth of penetration is below that of the point source.

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Li, Xinguo, Jun Zhao, and Qian Zhou. "Inner heat source model with heat and moisture transfer in soil around the underground heat exchanger." Applied Thermal Engineering 25, no. 10 (July 2005): 1565–77. http://dx.doi.org/10.1016/j.applthermaleng.2004.10.002.

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Guo, Tao, Guang Chen, and Cheng Zu Ren. "A Numerical Model to Determine Temperature Distribution in Aluminum Alloy (2A12) Micro-Cutting." Solid State Phenomena 175 (June 2011): 330–34. http://dx.doi.org/10.4028/www.scientific.net/ssp.175.330.

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Heat generation during cutting process affects the machined workpiece material and influences the cutting forces and tool wear. In this paper, a static thermal analysis model is developed to determine temperature rise in aluminum alloy (2A12) micro-cutting. The modified model is established based on two-dimensional steady state heat diffusion equation along with heat losses by convection film coefficients at the surfaces. A negative heat source is applied to simulate the heat loss during chip formation process. Effects of chip length and negative heat source on temperature distribution are discussed. The simulation results are compared with experiment data. The final results indicated that the model with negative heat source is more accurate than that without negative heat source and 20mm chip length give best temperature field fitting to the experiment.

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Stefanowicz, Ewelina, Małgorzata Szulgowska-Zgrzywa, and Natalia Fidorów-Kaprawy. "Analysis of the ground-source heat pump operation with various heat-carrier fluids in the lower heat source." E3S Web of Conferences 44 (2018): 00168. http://dx.doi.org/10.1051/e3sconf/20184400168.

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In the paper the analysis of the operation of ground-source heat pump with various heat-carrier fluids circulating in boreholes was made. The authors considered several aspects related to the heat-carrier fluid selection (freezing point, heat transfer capabilities, toxicity, pumping costs). The lower heat source analysis had been performed in Earth Energy Designer (EED) software. The analyses’ results reliability was assured by the ground-source model calibration made basing on the measurement data from on-site test stand. Analyses were performed for four heat-carrier fluids (two kinds of propylene glycol solutions – standard and with lower viscosity, water and nanofluid (water + CuO)) and in four variants of thermal load (design and actual loads both with and without active regeneration). It had been concluded that temperature of none of the fluids would drop under 0°C if the system was operated under actual thermal load. For design thermal load there would be a risk of the water freezing but it may be minimized by active regeneration or lower heat source enlargement by 20% (in analyzed case) each rising the mean fluid temperature by around 1.0-1.5 K. The use of other fluid in place of standard propylene glycol solution will give pumping energy savings.

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Kirdyashkin, A. A., A. G. Kirdyashkin, V. E. Distanov, and I. N. Gladkov. "ON HEAT SOURCE IN SUBDUCTION ZONE." Geodynamics & Tectonophysics 12, no. 3 (September 17, 2021): 471–84. http://dx.doi.org/10.5800/gt-2021-12-3-0534.

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The subduction of an oceanic plate is studied as the motion of a high-viscosity Newtonian fluid. The subducting plate spreads along the 670-km depth boundary under the influence of oppositely directed horizontal forces. These forces are due to oppositely directed horizontal temperature gradients. We consider the flow structure and heat transfer in the layer that includes both the oceanic lithosphere and the crust and moves underneath a continent. The heat flow is estimated at the contact between the subducting plate and the surrounding mantle in the continental limb of the subduction zone. Our study results show that the crustal layer of the subducting plate can melt and a thermochemical plume can form at the 670-km boundary. Our model of a thermochemical plume in the subduction zone shows the following: (1) formation of a plume conduit in the crustal layer of the subducting plate; (2) formation of a primary magmatic chamber in the area wherein the melting rate equals the rate of subduction; (3) origination of a vertical plume conduit from the primary chamber melting through the continent; (4) plume eruption through the crustal layer to the surface, i.e. formation of a volcano. Our experiments are aimed to model the plume conduit melting in an inclined flat layer above a local heat source. The melt flow structure in the plume conduit is described. Laboratory modeling have revealed that the mechanisms of melt eruption from the plume conduit differ depending on whether a gas cushion is present or absent at the plume roof.

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Yi, Sung-Chul. "Heat Transfer of a Smoldering Flammable Substrate. Part 1. Development of a Theoretical Model for the Heat Transfer of a Smoldering Substrate." Journal of Fire Sciences 15, no. 6 (November 1997): 462–80. http://dx.doi.org/10.1177/073490419701500603.

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Part 1 of this two part paper describes the development of a theo retical model for the interaction of the moving heat source and a solid substrate when they are in contact. For purposes of the model the substrate is assumed to act as a continuum and the Fourier equation for transient, three-dimensional conduction is solved using Laplace and Fourier transformations. Unlike most previous models, this model shows the explicit relations between the properties of the heat source and those of the substrate. Since the size, shape and speed of the heat source impact the ignition of substrate, considerable attention is devoted to evaluating these parameters. Results are presented which show the effects of the size, shape and speed of the heat source of the substrate.

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Sharma, Neha, Surjan Singh, and Dinesh Kumar. "Analytical Solution of Non Linear DPL Bioheat Transfer Model for Temperature Dependent Metabolic Heat Source During Thermal Therapy." International Journal of Innovative Technology and Exploring Engineering 11, no. 8 (July 30, 2022): 78–86. http://dx.doi.org/10.35940/ijitee.h9174.0711822.

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In this research paper, the simulation based modelling of heat transfer in tissue under periodic boundary condition has been considered. The dual phase lag bioheat transfer (DPLBHT) model is implemented for computation of the temperature based thermal therapy treatment. The elements of volumetric heat source such as perfusion of blood, metabolism heat source and external heat source are considered in nonlinear DPL model. In this paper we have taken three cases for metabolic heat source namely, constant, linear and exponential. The combined two numerical methods which are based on finite difference scheme and Runge Kutta (4,5) scheme are exerted to solve the non-linear problem. We compute the exact solution for particular case. Numerical conclusions which are computed by numerical hybrid method are equated with exact result. It has been found that non linear DPL model with exponential metabolic heat source is closed to exact solution. We also expressed the effect of different parameters such as relaxation time, perfusion rate, metabolic heat source parameter, associated blood perfusion heat, heat source because of heat flux and temperature gradient etc.

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Yan, Qiu Hui, and Ning Li. "Comparative Studies on Solar Combisystem by Different Auxiliary Heat Sources." Applied Mechanics and Materials 178-181 (May 2012): 76–79. http://dx.doi.org/10.4028/www.scientific.net/amm.178-181.76.

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This paper proposes a solar combisystem model with biomass boiler as its auxiliary heat source. Taking specific constructions of towns into consideration, solar combisystems with four different auxiliary heat sources——gas boiler, electric boiler, coal boiler and biomass boiler are compared from the aspects of comprehensive energy price, CO2 emissions and social benefits. The results show that, compared with the solar combisystems with conventional energy boilers as their auxiliary heat sources, the system with biomass boiler as its auxiliary heat source has favorable economic, social and environmental benefits.

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Katsura, Takao, Takashi Higashitani, Yuzhi Fang, Yoshitaka Sakata, Katsunori Nagano, Hitoshi Akai, and Motoaki OE. "A New Simulation Model for Vertical Spiral Ground Heat Exchangers Combining Cylindrical Source Model and Capacity Resistance Model." Energies 13, no. 6 (March 13, 2020): 1339. http://dx.doi.org/10.3390/en13061339.

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Considering the heat capacity inside vertical spiral ground heat exchanger (VSGHEX) in the simulation is one of the most noteworthy challenge to design the ground source heat pump (GSHP) system with VSGHEXs. In this paper, a new simulation model for VSGHEXs is developed by combining the ICS model with the CaRM. The developed simulation model can consider the heat capacity inside VSGHEX and provide dynamic calculation with high speed and appropriate precision. In order to apply the CaRM, the equivalent length was introduced. Then, the equivalent length was approximated by comparing the results of the CaRM and the numerical calculation. In addition, the calculation model of the VSGHEX was integrated into the design and simulation tool for the GSHP system. The accuracy of the tool was verified by comparing with the measurements. The error between supply temperatures of the measurements and calculation is approximately 2 °C at the maximum. Finally, assuming GSHP systems with VSGHEXs, whose spiral diameter was 500 mm and depth was 4 m, were installed in residential houses in Japan, the required numbers of VSGHEXs were estimated. The results showed a strong correlation between the total heating or cooling load and the required number. Therefore, the required number can be estimated by using the simplified approximate equation.

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Journal articles on the topic 'Heat source model'

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