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Academic literature on the topic 'Nusselt number ratio'

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Published: 4 June 2025

Last updated: 15 July 2025

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Journal articles on the topic "Nusselt number ratio"

Okba, Singgah khairun, Ridwan Ridwan, and Iwan Setyawan. "CFD Simulation With Ansys Effect Of Twisted Tape Ratio On Nusselt Number and Reynold Number Solar Collector." Eksergi 18, no. 3 (2022): 186–89. https://doi.org/10.32497/eksergi.v18i3.3855.

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Solar collector is one of the tools used to harness solar power and then convert it into heat which is used to heat water. The solar collector used is a flat plate type solar collector, the drawback of this solar collector is its low efficiency value. One method that can be used to increase its efficiency is to add twisted tape. Twisted tape serves to increase the value of the nusselt number and reynold number, where the increasing nusselt number and reynold number means the efficiency will increase, the Twisted Tape Ratio is the ratio between the distance of two peaks (H) and the width of the

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Ligrani, P. M., and G. I. Mahmood. "Spatially Resolved Heat Transfer and Friction Factors in a Rectangular Channel With 45-Deg Angled Crossed-Rib Turbulators." Journal of Turbomachinery 125, no. 3 (2003): 575–84. http://dx.doi.org/10.1115/1.1565353.

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Spatially resolved Nusselt numbers, spatially averaged Nusselt numbers, and friction factors are presented for a stationary channel with an aspect ratio of 4 and angled rib turbulators inclined at 45 deg with perpendicular orientations on two opposite surfaces. Results are given at different Reynolds numbers based on channel height from 10,000 to 83,700. The ratio of rib height to hydraulic diameter is .078, the rib pitch-to-height ratio is 10, and the blockage provided by the ribs is 25% of the channel cross-sectional area. Nusselt numbers are given both with and without three-dimensional con

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Burgess, N. K., M. M. Oliveira, and P. M. Ligrani. "Nusselt Number Behavior on Deep Dimpled Surfaces Within a Channel." Journal of Heat Transfer 125, no. 1 (2003): 11–18. http://dx.doi.org/10.1115/1.1527904.

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Experimental results, measured on a dimpled test surface placed on one wall of a channel, are given for a ratio of air inlet stagnation temperature to surface temperature of approximately 0.94, and Reynolds numbers ReH from 12,000 to 70,000. These data include friction factors, local Nusselt numbers, spatially-resolved local Nusselt numbers, and globally-averaged Nusselt numbers. The ratio of dimple depth to dimple print diameter δ/D is 0.3, and the ratio of channel height to dimple print diameter is 1.00. These results are compared to measurements from other investigations with different rati

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REDDY, P. VENKATA, G. S. V. L. NARASIMHAM, S. V. RAGHURAMA RAO, T. JOHNY, and K. V. KASIVISWANATHAN. "CFD ANALYSIS OF CONJUGATE NATURAL CONVECTION IN A VERTICAL ANNULUS." International Journal of Computational Methods 05, no. 01 (2008): 63–89. http://dx.doi.org/10.1142/s021987620800139x.

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Conjugate natural convection in a vertical annulus with a centrally located vertical heat generating rod is studied numerically. The governing equations are discretized on a staggered mesh and are solved using a pressure-correction algorithm. A parametric study is performed by varying the Grashof number, aspect ratio, and the solid-to-fluid thermal conductivity ratio over wide ranges with the Prandtl number fixed at 0.7. Results are presented for the variation of several quantities of interest such as the local Nusselt numbers on the inner and outer boundaries, the axial variation of the cente

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Burgess, N. K., and P. M. Ligrani. "Effects Of Dimple Depth on Channel Nusselt Numbers and Friction Factors." Journal of Heat Transfer 127, no. 8 (2004): 839–47. http://dx.doi.org/10.1115/1.1994880.

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Experimental results, measured on dimpled test surfaces placed on one wall of different rectangular channels, are given for a ratio of air inlet stagnation temperature to surface temperature of approximately 0.94, and Reynolds numbers based on channel height from 9940 to 74,800. The data presented include friction factors, local Nusselt numbers, spatially averaged Nusselt numbers, and globally averaged Nusselt numbers. The ratios of dimple depth to dimple print diameter δ∕D are 0.1, 0.2, and 0.3 to provide information on the influences of dimple depth. The ratio of channel height to dimple pri

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Su, Duan, He, Ma, and Xu. "Thermally Developing Flow and Heat Transfer in Elliptical Minichannels with Constant Wall Temperature." Micromachines 10, no. 10 (2019): 713. http://dx.doi.org/10.3390/mi10100713.

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Laminar convective heat transfer of elliptical minichannels is investigated for hydrodynamically fully developed but thermal developing flow with no-slip condition. A three-dimensional numerical model is developed in different elliptical geometries with the aspect ratio varying from 0.2 to 1. The effect of Reynolds number (25 ≤ Re ≤ 2000) on the local Nusselt number is examined in detail. The results indicate that the local Nusselt number is a decreasing function of Reynolds number and it is sensitive to Reynolds number especially for Re less than 250. The effect of aspect ratio on local Nusse

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Won, S. Y., N. K. Burgess, S. Peddicord, and P. M. Ligrani. "Spatially Resolved Surface Heat Transfer for Parallel Rib Turbulators With 45 Deg Orientations Including Test Surface Conduction Analysis." Journal of Heat Transfer 126, no. 2 (2004): 193–201. http://dx.doi.org/10.1115/1.1668046.

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Spatially resolved Nusselt numbers, spatially-averaged Nusselt numbers, and friction factors are presented for a stationary channel with an aspect ratio of 4 and angled rib turbulators inclined at 45 deg with parallel orientations on two opposite surfaces. Results are given at different Reynolds numbers based on channel height from 9000 to 76,000. The ratio of rib height to hydraulic diameter is 0.078, the rib pitch-to-height ratio is 10, and the blockage provided by the ribs is 25 percent of the channel cross-sectional area. Nusselt numbers are determined with three-dimensional conduction con

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Zhang, Yan, and Hai Wei Xie. "The Convective Heat Transfer in Furcated Blood Vessels." Applied Mechanics and Materials 475-476 (December 2013): 1599–602. http://dx.doi.org/10.4028/www.scientific.net/amm.475-476.1599.

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A finite element model was developed to simulate the 3-D velocity and temperature distributions in a vessel system including a bifurcated blood vessel and two branches. The effect of the angel between vessels and bifurcation ratio were taken into account, and the local Nusselt number at three typical radial angels and the mean Nusselt number on a section in the branching vessel were obtained. Results show that: the flow and temperature fields were highly unlike the distributions of a single vessel; the local Nusselt number were different at different radial angels; In the entrance region of th

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Aparna, K., K. Karthik, and K. N. Seetharamu. "Natural Convection Flows in Porous Square Enclosures with Different Aspect Ratios." Applied Mechanics and Materials 592-594 (July 2014): 1657–61. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.1657.

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Natural convection is studied numerically using finite element based computational procedure. The enclosure used for flow and heat transfer analysis has been bounded by adiabatic top wall, constant temperature cold vertical walls and a horizontal bottom wall. The grid independent study has been made with different grids to yield consistent values. Different grid sizes 30x30, 40x40, 50x50 uniform meshes have been studied. Study shows the convergence of average Nusselt number for a grid size of 41x41. Hence a grid size of 40x40 is used in all computations. Nusselt numbers are computed for differ

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Ou, S., J. C. Han, A. B. Mehendale, and C. P. Lee. "Unsteady Wake Over a Linear Turbine Blade Cascade With Air and CO2 Film Injection: Part I—Effect on Heat Transfer Coefficients." Journal of Turbomachinery 116, no. 4 (1994): 721–29. http://dx.doi.org/10.1115/1.2929465.

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The effect of unsteady wake flow and air (D.R. = 1.0) or CO2 (D.R. = 1.52) film injection on blade heat transfer coefficients was experimentally determined. A spoked wheel-type wake generator produced the unsteady wake. Experiments were performed on a five-airfoil linear cascade in a low-speed wind tunnel at the chord Reynolds number of 3 × 105 for the no-wake case and at the wake Strouhal numbers of 0.1 and 0.3. Results from a blade with three rows of film holes in the leading edge region and two rows each on the pressure and suction surfaces show that the Nusselt numbers are much higher than

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Dissertations / Theses on the topic "Nusselt number ratio"

Guy, Ashley Ray. "Effect of Blowing Ratio on the Nusselt Number and Film Cooling Effectiveness Distributions of a Showerhead Film Cooled Blade in a Transonic Cascade." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/43764.

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This paper investigates the effect of blowing ratio on the film cooling performance of a showerhead film cooled first stage turbine blade. The blade was instrumented with double-sided thin film heat flux gages to experimentally characterize the Nusselt number and film cooling effectiveness distributions over the surface of the blade. The blade was arranged in a two-dimensional, linear cascade within a transonic, blowdown type wind tunnel. The wind tunnel freestream conditions were varied over two exit Mach numbers, Me=0.78 and Me=1.01, with an inlet freestream turbulence intensity of 12% ,

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Haugen, Christina G. M. "Numerical Investigation of Thermal Performance for Rotating High Aspect Ratio Serpentine Passages." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1412698677.

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"High-precision Nusselt number and local temperature measurements in very small aspect-ratio turbulent thermal convection." 2006. http://library.cuhk.edu.hk/record=b5892789.

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Ren Liyuan = 小寬高比熱對流中高精度Nusselt數和局部溫度測量 / 任立元. Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. Includes bibliographical references (leaves 64-66). Text in English; abstracts in English and Chinese. Ren Liyuan = Xiao kuan gao bi re dui liu zhong gao jing du Nusselt shu he ju bu wen du ce liang / Ren Liyuan. Abstract (in English) --- p.i Abstract (in Chinese) --- p.ii Acknowledgements --- p.iii Table of Contents --- p.iv List of Figures --- p.vi List of Tables --- p.ix Chapters Chapter I. --- Turbulent Rayleigh-Benard Convection --- p.1 Chap

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"Aspect-ratio dependence of the Nusselt number and boundary layer properties in Rayleigh-Bénard turbulent convection." 2005. http://library.cuhk.edu.hk/record=b5896446.

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Cheung Yin Har = 瑞利-柏納德湍流對流中Nusselt與縱橫比的關係以及邊界層性質的研究 / 張燕霞. Thesis submitted in: October 2004. Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. Includes bibliographical references (leaves 115-119). Text in English; abstracts in English and Chinese. Cheung Yin Har = Ruili-Bonade tuan liu dui liu zhong Nusselt yu zong heng bi de guan xi yi ji bian jie ceng xing zhi de yan jiu / Zhang Yanxia. Abstract --- p.i 摘要 --- p.iii Acknowledgments --- p.iv Contents --- p.v List of Figures --- p.vii List of Tables --- p.x Chapter Chapter 1 --- Introduction -

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Wang, Hsun, and 王珣. "Nusselt Numbers as Composite Functions of the Aspect Ratio and Included Angle in Single and Two-Pass Parallelogram Channels." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/u625rd.

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Book chapters on the topic "Nusselt number ratio"

Kepekçi, Haydar. "CFD Analysis of the Influence of Twisted Tape Width and Thickness on Flow Characteristics in Pipe Flow." In Doğanın Ritmi, Enerjinin Dönüşümü, Üretimin Gücü (I. Ulusal Enerji Dönüşümü ve Sürdürülebilirlik Konferansı). İstanbul Gedik Üniversitesi, 2025. https://doi.org/10.61150/gedikyay.250305.

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This study investigates the impact of twisted tape geometry on heat transfer performance in pipe flow, focusing on width ratio, thickness, and flow velocity variations. A 25 mm diameter and 1-meter-long pipe were utilized, with water as the working fluid. The analyses considered flow velocities of 0.05 m/s and 0.2 m/s, twisted tape width ratios (20%, 40%, 80%), and thicknesses (0.5 mm, 1 mm, 2 mm). Key parameters such as Reynolds number (Re), Nusselt number (Nu), friction factor (f), and pressure drop (ΔP) were calculated. The results revealed that increasing the width ratio and thickness of the twisted tape significantly influenced the hydraulic diameter, altering the Re and Nu values. Higher width ratios improved heat transfer but increased friction and pressure loss. Similarly, thicker twisted tapes elevated flow resistance, affecting pressure loss and heat transfer performance. At higher flow velocities, turbulent flow enhanced heat transfer, reflected by increased Nu, though at the expense of friction and pressure losses. Baseline comparisons without twisted tape showed significantly lower heat transfer performance. These findings highlight the critical role of optimized twisted tape design in balancing heat transfer efficiency and pressure loss for improved system performance.

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LOCK, G. S. H. "Evaporation." In Latent Heat Transfer. Oxford University PressOxford, 1994. http://dx.doi.org/10.1093/oso/9780198562856.003.0006.

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Abstract In this chapter we will consider various forms of evaporation, covering both bipartitioned and dispersed systems. We may easily anticipate some of the non-dimensional groups which affect evaporation rates: for example, the ratio of sensible to latent heat, the Jakob number. To begin with, we limit ourselves to situations in which evaporation is essentially the inverse of condensation, thus permitting the use of ideas and results presented in the previous chapter. In particular, we will consider the classical Nusselt problem with condensation replaced by evaporation at the interface.

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Tsutsumi, T., S. Takeuchi, and T. Kajishima. "Effect of Solid And Liquid Heat Conductivities on Two-Phase Heat and Fluid Flows." In Discrete Element Modelling of Particulate Media. The Royal Society of Chemistry, 2012. http://dx.doi.org/10.1039/bk9781849733601-00021.

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Liquid-solid two-phase flow with heat transfer is simulated, and the effects of temperature gradient within a solid object and particle mobility on heat transfer are studied. The interaction between fluid and particles is considered with our original immersed solid approach on a rectangular grid system. A discrete element model with soft-sphere collision is applied for particle-particle interaction. Governing equation of temperature is time-updated with an implicit treatment for the diffusion term, which enables stable simulation with particles of very high/low ratios of heat conductivity (from 1/1000 to 1000) to fluid. The local heat flux at the fluid-solid interface is carefully discretised and incorporated into the implicit scheme of temperature. The method is applied to a 2-D confined flow including multiple particles under a high Rayleigh number condition. Heat transfer and particle behaviours are studied for different ratios of heat conductivity (solid to liquid) and solid volume fractions. For a relatively low solid volume fraction, a transition of particulate flow pattern is observed depending on the heat conductivity ratio; the cases with high ratios of heat conductivities exhibit simple (single or double) circulating flows, whereas low heat conductivity ratio causes complicated flow patterns involving multiple circulation of particles, resulting in low Nusselt number. The above simulation results, together with the heat transfer properties under a near-packed condition, highlight the effect of temperature distributions within the particles and liquid.

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Benhamou, Jaouad, Salaheddine Channouf, Youssef Admi, et al. "Numerical Study of Natural Convection Energy Transfer in a Grooved Cavity Using the Hybrid Lattice Boltzmann Method." In Advances in Environmental Engineering and Green Technologies. IGI Global, 2025. https://doi.org/10.4018/979-8-3693-9924-8.ch015.

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In this work, natural convection in a grooved rectangular cavity with aspect ratio R =2 is analyzed using a hybrid numerical approach combining the lattice Boltzmann method and the finite-difference technique. The introduction of two grooves in the cavity geometry aims to improve heat transfer passively, using air as the fluid with a Prandtl number of 0.71. The results show a significant improvement in heat transfer efficiency, with a 76% gain in Nusselt number at a Rayleigh number (Ra) set at 10^3 and 43% at Ra=10^5, compared with the conventional Rayleigh-Bénard configuration. These improvements are attributed to modified flow structures and deformed isotherms near the grooves, favoring complex fluid dynamics and improved heat exchange. These results suggest that grooved geometries can be used effectively to enhance heat transfer in natural convection, making them suitable for a variety of industrial applications.

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Horimek, Abderrahmane, Farhat Abdelmoumene, and Noureddine Ait-Messaoudene. "Numerical Study of Natural Convection between Two Concentric Ellipses with Different Shapes and Imposed Temperatures." In Mechanical Engineering Technologies and Applications: Volume 2. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815124125123020009.

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In this work, the laminar natural convection problem for a Newtonian fluid confined between two concentric ellipses is solved numerically. Two cases of heating are assumed, an inner wall at high temperature (TH ) and an external one at low temperature (TC ), then the opposite. Starting from the case of two circles (ellipses with equal diameters) and arriving at two ellipses, 25 geometries are studied for each type of heating, which gives 50 geometries in total. The effects of Rayleigh number (Ra), aspect ratio in addition to the ellipses orientations are investigated. The dynamic and thermal fields as well as the geometry average Nusselt number calculation (Nuavg=(Nuavo+Nuavi)/2) are analyzed. Nuavg values are ranked at the end in a descending order to show which geometry offers the largest heat exchange rate and vice versa, that is something very useful in practice. It should be noted that a good choice of the geometry shape may lead to have a more homogeneous thermal field, a result which goes against the stratifying effect of natural convection that has sometimes to be avoided.

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Abdulrahman Alpha, Ndah, and Aondoyila Kuhe. "Heat Transfer Enhancement on Staggered Perforated Circular Pin-Fin Heat Sink: An Experimental Assessment." In Current Research in Thermal Conductivity [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1007019.

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This experimental study examines how forced convective flow affects heat transfer properties in a rectangular channel with staggered pin fins featuring different perforation patterns under constant heat flux conditions across Reynolds numbers (Re) ranging from 2.0 × 103 to 12 × 103. The study compares cylindrical pin fins with solid pin fins and those featuring circular longitudinal (L), longitudinal/transverse (LT), and longitudinal/transverse/vertical (LTV) perforations to determine optimal perforation configurations for enhanced heat transfer performance. The experiment uses a Peltier module to generate heat on one side, utilizing the Armfield Free and Forced Convection Heat Transfer Service Units HT 19 and HT10XC. The results showed that perforated pins significantly raise Nusselt number (Nu) over solid pins: 7% for L, 30% for LT, and 64% for LTV perforations. Pressure drops are reduced by 10% for L, 17% for LT, and 25% for LTV perforations relative to solid pins. At lower Reynolds numbers, the overall enhancement ratio peaks, notable for reaching a 40% rise with LTV-perforated pin fins. Additionally, fin effectiveness improves significantly: 14, 34, and 57% higher for L, LT, and LTV perforated pin-fin arrays, respectively. This study showcases potential applications in electronic cooling systems, promising improved heat transfer efficiency.

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Rincón-Casado, Alejandro, and Francisco José Sánchez de la Flor. "A New Forced Convection Heat Transfer Correlation for 2D Enclosures." In Applications of Computational Fluid Dynamics Simulation and Modeling. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.99375.

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This work presents a new parametric correlation for 2D enclosures with forced convection obtained from CFD simulation. The convective heat transfer coefficient of walls for enclosures depends on the geometry of the enclosure and the inlet and outlet openings, the velocity and the air to wall temperature difference. However, current correlations not dependent on the above parameters, especially the position of the inlet and outlet, or the temperature difference between the walls. In this work a new correlation of the average Nusselt number for each wall of the enclosure has been developed as a function of geometrical, hydrodynamic and thermal variables. These correlations have been obtained running a set of CFD simulations of a 3 m high sample enclosure with an inlet and outlet located at opposite walls. The varying parameters were: a) the aspect-ratio of the enclosure (L/H = 0.5 to 2), b) the size of the inlet and outlet (0.05 m to 2 m), c) the inlet and outlet relative height (0 m to 3 m high), and d) the Reynolds number (Rein = 103 to 105). Furthermore, a parametric analysis has been performed changing the temperature boundary conditions at the internal wall and founds a novel correlation function that relates different temperatures at each wall. A specifically developed numerical model based on the SIMPLER algorithm is used for the solution of the Navier–Stokes equations. The realisable turbulence k-ε model, and an enhanced wall-function treatment have been used. The heat transfer rate results obtained are expressed through dimensionless correlation-equations. All developed correlations have been compared with CFD simulations test cases obtaining a R2 = 0.98. This new correlation function could be used in building energy models to enhance accuracy of HVAC demands calculation and estimate the thermal load.

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Conference papers on the topic "Nusselt number ratio"

Burgess, N. K., M. M. Oliveira, and P. M. Ligrani. "Nusselt Number Behavior on Deep Dimpled Surfaces Within a Channel." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32941.

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Experimental results, measured on a dimpled test surface placed on one wall of a channel, are given for a ratio of air inlet stagnation temperature to surface temperature of approximately 0.94, and Reynolds numbers from 12,000 to 70,000. These data include friction factors, local Nusselt numbers, spatially-resolved local Nusselt numbers, and globally-averaged Nusselt numbers. The ratio of dimple depth to dimple print diameter δ/D is 0.3, and the ratio of channel height to dimple print diameter is 1.00. These results are compared to measurements from other investigations with different ratios o

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Siddiqui, Wajeeha, Zafar Abbas, Imran Akhtar, and Muhammad Saif Ullah Khalid. "Nusselt Number Dependence on Aspect Ratio and Rayleigh Number: A Numerical Study of Rayleigh-Benard Instability." In ASME 2022 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/fedsm2022-87897.

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Abstract In this paper, Rayleigh-Benard Convection (RBC) is investigated in a two-dimensional vertical cavity with the horizontal temperature gradient for Rayleigh numbers (Ra) up to 20000. The velocity and temperature fields along with the Nusselt number (Nu) are examined and discussed for various cases of aspect ratios (AR); 1 ≤ AR ≤ 100, along with examining the critical aspect ratio (ARcr). It is found that in the case of horizontal temperature gradient, convection starts at critical Rayleigh number ≈ 370. It is also observed that the fluid motion is initially restricted to wall proximity,

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Shih, Tom I.-Ping, and Srisudarshan Krishna Sathyanarayanan. "A New Nusselt Number for Complicated Configurations." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17114.

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Convective heat transfer over surfaces is generally presented in the form of the heat-transfer coefficient (h) or its nondimensional form, the Nusselt number (Nu). Both require the specification of the free-stream temperature (Too) or the bulk (Tb) temperature, which are clearly defined only for simple configurations. For complicated configurations with flow separation and multiple temperature streams, the physical significance of Too and Tb becomes unclear. In addition, their use could cause the local h to approach positive or negative infinity if Too or Tb is nearly the same as the local wal

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Burgess, N. K., and P. M. Ligrani. "Effects of Dimple Depth on Nusselt Numbers and Friction Factors for Internal Cooling in a Channel." In ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-54232.

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Experimental results, measured on dimpled test surfaces placed on one wall of different channels, are given for a ratio of air inlet stagnation temperature to surface temperature of approximately 0.94, and Reynolds numbers based on channel height from 9,940 to 74,800. The data presented include friction factors, local Nusselt numbers, spatially-averaged Nusselt numbers, and globally-averaged Nusselt numbers. The ratios of dimple depth to dimple print diameter δ/D are 0.1, 0.2, and 0.3 to provide information on the influences of dimple depth. The ratio of channel height to dimple print diameter

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van Rij, Jennifer, Tim Ameel, and Todd Harman. "Constant Wall Temperature Nusselt and Poiseuille Numbers in Rectangular Microchannels." In ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference collocated with the ASME 2007 InterPACK Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ht2007-32465.

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Slip flow convective heat transfer and friction loss characteristics are numerically evaluated for constant wall temperature rectangular microchannels. The effects of rarefaction, accommodation coefficients, aspect ratio, second-order slip boundary conditions, axial conduction, and viscous dissipation with flow work are each considered. Second-order slip boundary conditions, axial conduction, and viscous dissipation with flow work effects have not been studied previously for rectangular channel slip flows. The effects of each of these parameters on the numerically computed convective heat tran

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Mahmood, G. I., P. M. Ligrani, and S. Y. Won. "Spatially-Resolved Heat Transfer and Flow Structure in a Rectangular Channel With 45° Angled Rib Turbulators." In ASME Turbo Expo 2002: Power for Land, Sea, and Air. ASMEDC, 2002. http://dx.doi.org/10.1115/gt2002-30215.

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Spatially-resolved Nusselt numbers and flow structure are presented for a stationary channel with an aspect ratio of 4 and angled rib turbulators inclined at 45° with perpendicular orientations on two opposite surfaces. The flow structure results include time-averaged distributions of streamwise velocity and total pressure, surveyed over flow cross-sectional planes, as well as flow visualization images and friction factors. Results are given at different Reynolds numbers based on channel height from 270 to 90,000. The ratio of rib height to hydraulic diameter is .078, the rib pitch-to-height r

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Cheng, Minter. "Fluid Flow and Heat Transfer Around Two Circular Cylinders in Side-by-Side Arrangement." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56005.

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Incompressible flows passing through two circular cylinders in side-by-side arrangement are investigated numerically. The calculations are carried out with pitch ratios from 1.1 to 2.0 at Reynolds number of 1000. The flow and temperature fields, flow interference, and the local and the mean Nusselt numbers are studied in this research. It is observed that for the pitch ratios in the range of 2.0 and 1.5, the emerging jet between cylinders deflects and one wide and one narrow wakes behind the cylinders are formed. The gap flow velocity increases as the pitch ratio decreases and consequently inc

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Zhang, Bo-lun, Hui-ren Zhu, Tao Guo, Chun-yi Yao, and Zhong-yi Fu. "Numerical Study on Heat Transfer and Flow Characteristics in Double Turning Areas Ribbed Serpentine Channel With Lateral Outflow." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-90143.

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Abstract The double turning areas ribbed serpentine channel with lateral outflow is an important structure for designing the internal systems of turbine blade. The current work similarly simplifies the internal channel of the real blade. The Nusselt number and pressure coefficient distribution of the double turning areas ribbed serpentine channel with different outflow ratios are numerically researched under static and rotating conditions. The Realizable k-ε turbulence model with enhanced wall treatment is used in the numerical simulation. The inlet Reynolds number is 11000. The rotation numbe

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Nouri, Behnam, Knut Lehmann, and Arnold Kühhorn. "Investigations on Nusselt Number Enhancement in Ribbed Rectangular Turbine Blade Cooling Channels of Different Aspect Ratios and Rotation Numbers." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-94710.

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In the drive for higher cycle efficiencies in gas turbine engines, turbine blades are seeing an increasingly high heat load. This in turn demands improvements in the internal cooling system and a better understanding of both the level and distribution of the internal heat-transfer. A typical approach to enhance the internal cooling of the turbine blade is by casting angled ‘low blockage’ ribs on the walls of the cooling channels. The objective of the present paper is to determine the detailed Nusselt number distribution in rectangular internal channels with ribs. This knowledge can be used to

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Fu, Wen-Lung, Lesley M. Wright, and Je-Chin Han. "Buoyancy Effects on Heat Transfer in Five Different Aspect-Ratio Rectangular Channels With Smooth Walls and 45-Degree Ribbed Walls." In ASME Turbo Expo 2005: Power for Land, Sea, and Air. ASMEDC, 2005. http://dx.doi.org/10.1115/gt2005-68493.

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Abstract:

This paper experimentally studies the effects of the buoyancy force and channel aspect ratio on heat transfer in two-pass rotating rectangular channels with smooth walls and 45° ribbed walls. The channel aspect ratios include 4:1, 2:1, 1:1, 1:2 and 1:4. Four Reynolds numbers are studied: 5000, 10000, 25000 and 40000. The rotation speed is fixed at 550 rpm for all tests, and for each channel, two channel orientations are studied: 90° and 45° or 135°, with respect to the plane of rotation. Rib turbulators are placed on the leading and trailing walls of the channels at an angle of 45° to the flow

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