Academic literature on the topic 'Vertical tube baffle'

Multichannel borehole hydrophone strings are a low-cost, low-risk, alternative to borehole clamping geophones. Vertical seismic profile (VSP) data collected with hydrophones, however, suffer from high-amplitude coherent tube-wave noise. This reduces the usable data to the first arrivals and traveltimes for check-shot surveys. To significantly reduce tube-wave noise from VSP data acquired with hydrophones, we have designed and tested a novel tube-wave attenuation baffle. The effectiveness of the baffle was first verified in a laboratory-scale experiment and then in a borehole drilled into a hardrock environment. The laboratory experiments tested the performance of four different baffle topologies, whereby the best performing topology was the semirigid corrugated pipe baffle. This design reduced the amplitude of the tube wave with more than 40 dB and was logistically easy to deploy. The field experiment investigated the effectiveness of three different semirigid corrugated pipe baffle topologies in a PQ (123 mm) diamond drillhole in Western Australia. Here, we found that the semirigid corrugated pipe baffle was effective in disrupting tube-wave propagation. The 100 mm diameter baffle achieved an impressive 60 dB of tube-wave attenuation, whereas the 50 mm baffle had a modest attenuation of 10–15 dB. This suggests that the performance of this new type of baffle is best when the diameter of the baffle is closely matched to the diameter of the borehole. The results of these experiments have significant implications because hydrophone arrays with a large number of receivers are comparatively inexpensive and simpler to deploy than borehole geophone counterparts. The development of hydrophone arrays that are free of interfering borehole modes could allow VSPs to be acquired in situations in which seismic-polarity information is not required and could help VSP gain traction in cases in which the cost of acquisition has precluded its use until now.

The performance of ethanol distillation is determined by the type of reboiler used in the distillation column. This study aims to determine the effect of differences in diameter and height of internal reboiler tubes, as well as feed content on ethanol distillate concentration and distillation yield. The research was conducted on a batch ethanol distillation process using a rectified distillation device with an internal vertical tubular baffle reboiler using different diameters and tube height, namely 1.5, 1, and 0.5 inches of diameter, and 8, 6, and 4 cm of tube heights. Materials or feeds in this study were ethanol solutions with levels of 10%, 20%, and 30% v/v. The results showed that the highest ethanol distillate content of 97.17% v/v (average) was achieved in the distillation process using an internal reboiler with a diameter of 0.5”, a tube height of 8 cm, and a feed content of 10%. Geometry affected the heat transfer process in the internal reboiler of a distillation device so that it affected the distillation results.Keywords: distillation; ethanol; internal reboiler: performanceA B S T R A KKinerja alat distilasi etanol ditentukan oleh jenis reboiler yang digunakan pada kolom distilasi. Penelitian ini bertujuan untuk menentukan pengaruh perbedaan diameter dan tinggi tabung internal reboiler, serta kadar umpan terhadap kadar etanol distilat dan rendemen distilasi. Penelitian dilakukan pada proses distilasi etanol secara batch menggunakan alat distilasi rektifikasi dengan internal reboiler jenis Vertical Tubular Baffle yang berbeda ukuran diameter dan tinggi tabungnya, yaitu diameter 1,5, 1 dan 0,5 inci, serta tinggi tabung 8, 6 dan 4 cm. Bahan atau umpan pada penelitian ini adalah larutan etanol berkadar 10%, 20% dan 30% v/v. Hasil penelitian didapatkan kadar etanol distilat yang paling tinggi dengan kadar rata-rata 97,17% v/v dicapai pada proses distilasi dengan internal reboiler berukuran diameter 0,5 inci, dan tinggi tabung 8 cm dan kadar umpan 10%. Geometri berpengaruh pada proses perpindahan panas di dalam internal reboiler suatu alat distilasi sehingga berpengaruh terhadap hasil distilasi.Kata kunci: distilasi; etanol; internal reboiler; kinerja

The long spiral tube with its deep rifle groove make a long duration for Electrochemical Machining (ECM) and mass of floccule precipitate, esulting in bottleneck to maintain cleanliness of electrolyte in sedimentation basin at machining. The design scheme of duplex vertical flow electrolyte basin was proposed. The surface hydraulic power, available cubage, flooding area, sludge blanket level (SBH) and sludge tank height were calculated in terms of the electrical current, sinking speed of Fe(OH)3, flux of electrolyte. The streamline in the basin were simulated by COMSOL based elementary draft. The flow speed at intake of sludge blanket and the exit of clarified were analyzed with diameter of cone-meatus of center tube being altered and the space between it and baffle-board shifted, and the sedimentation basin is optimized.

We evaluated the capabilities of vertical seismic profiling (VSP) for imaging the complex heterogeneous unconsolidated sedimentary structures at a shallow site. We deployed a 24‐level hydrophone array with 0.5-m level spacing down a preexisting poly vinyl chloride (PVC) cased well. Data acquisition time was quick. Only 15 multioffset shot points using a hammer‐on‐plate source were needed to acquire reflection data between the water table at 3 m and the bedrock at 35 m to produce a depth section image. This image extended 9 m from the receiver well, yielding resolutions between fresh‐water‐bearing sands and impermeable muds and clays of better than 1 m. Depth accuracy of the image was confirmed by good correlation with cone penetrometer logs. We used conventional wavefield separation and VSP-CDP mapping techniques to image the data. Tube waves, created by seismic arrivals at cross‐sectional area changes in the borehole fluid column, were the primary source of coherent noise in the data. The tube‐wave arrival structure was complicated by the hydrophone array, which generated and scattered tube waves at each hydrophone pod. To combat the tube wave interference, we inserted closed‐cell‐foam baffles between elements. The baffles attenuated and slowed the tube waves, and reduced generation and scattering. A comparison between unbaffled and baffled VSP data showed that baffling increased the maximum useful frequency from 300 Hz to over 900 Hz. By contrast, surface shot data recorded at the same site, using buried 40-Hz vertical geophones, exhibited useful frequencies of less than 250 Hz. In addition, coherent noise in surface shot records caused by air waves and first arrivals made it very difficult to identify shallow reflections above 25 m. Reflections from depths as shallow as 10 m were easy to identify in the baffled VSP data.

This paper discusses the problems of instable combustion, serious slag, outfire in boilers with horizontal concentrated boiler, taking a 410t/h boiler as the sample. Through experimental researches on different adjusting characteristics of horizontal concentrated burners, it is found that the coal air mixture has different characteristics in velocity and concentration when the baffles are respectively left in the centrifugal or centripetal side of the bent pipes, and that the baffles wear pattern also depends on individual installation location. During many cold and hot commissioning tests, the effective height of baffles is regulated and the original refractory belts are replaced to vertical evenly spaced bare-tube wall. After taking the above measures, the significant problems in the boiler are settled and the economics and safety operation performance is improved considerably. Thus the paper can offer certain references for other boilers with horizontal concentrated burners.

The article describes a theoretical model of two-dimensional flow of a homogeneous liquid in a cylindrical space delimited by the shell of the mixing tank with a conical bottom, radial baffles and a high-speed axial impeller rotating in a cylindrical draft-tube. By means of the analytical solution of vortex flow equation the mean time flow of turbulent liquid in the vertical cross section of the vessel may be described in the form of Stokes stream function or mean velocity components. The results of theoretical description of the flow are in a good agreement with the experimental values measured by a Pitot direction tube and a hot film anemometer.

A literatura corrente possui informações limitadas sobre o projeto da área de troca térmica de tanques com jaqueta, serpentina helicoidal, serpentina espiral e chicana tubular vertical, em operação com fluidos não-Newtonianos. A presente tese teve por objetivo principal analisar a transferência de calor, potência consumida e ampliação de escala em tanques com impulsores mecânicos na agitação de fluidos não-Newtonianos com duas superfícies de transmissão de calor, chicana tubular vertical e serpentina em espiral. O trabalho também visou fornecer métodos de ampliação de escala de tanques com agitação para fluidos não-Newtonianos que sigam o modelo reológico da lei das potências. A unidade experimental contemplou dois tanques de acrílico, com volume de 10 litros e 50 litros, respectivamente, chicanas tubulares verticais e serpentina em espiral. Os impulsores mecânicos utilizados foram o axial com 4 pás inclinadas a 45° e o radial turbina com 6 pás planas. Como fluidos utilizaram-se soluções aquosas de carboximetilcelulose (0,5%, 1,0% e 1,5%), solução aquosa de carbopol 940 (1,5%), solução aquosa de sacarose (50%) e água. Todos os experimentos foram conduzidos em batelada. Com os dados obtidos, empregou-se o uso de regressões para a obtenção da Equação de Nusselt, as quais forneceram valores de coeficiente de determinação ajustados entre 0,83 e 0,89 com Reynolds no intervalo de 20 a 405000, Prandtl na faixa de 4 a 6400 e índice reológico do modelo da lei das potências entre 0,45 e 1,00. Observou-se que no aquecimento realizado com a chicana tubular vertical, o impulsor radial forneceu coeficientes de convecção 20% acima quando comparado com o impulsor axial, entretanto o consumo de potência foi cerca de 66% maior em relação ao impulsor axial. No caso da serpentina espiral, o impulsor axial promoveu coeficientes de convecção por volta de 15% superiores em relação ao impulsor radial com um consumo de potência 65% menor. Desse modo, em processos em que não é necessária uma elevada turbulência, recomenda-se o uso do impulsor axial com a serpentina espiral, porém, se o processo demandar uma turbulência significativa, deve-se usar o impulsor radial com a chicana tubular vertical. Em uma última análise, os modelos não-lineares obtidos para ampliação de escala forneceram erros entre 11% e 20% na predição da rotação no tanque industrial, os quais são válidos para Reynolds modificados de Metzner e Otto (1957) na faixa de 20 a 4000 e para fluidos não-Newtonianos pseudoplásticos com índices reológicos entre 0,45 e 1,00.
Current literature has limited information on the design of the thermal exchange area of tanks with jacket, helical coil, spiral coil and vertical tuber baffle, in operation with non-Newtonian fluids. The main purpose of this thesis was to analyze heat transfer, power consumption and scale-up in tanks with mechanical impellers in the agitation of non-Newtonian fluids with two heat transfer surfaces, vertical tube baffle and spiral coil. The work also aimed to provide methods of scale-up tank scale with agitation for non-Newtonian fluids that follow the rheology model of the law of powers. The experimental unit included two acrylic tanks, with a volume of 10 liters and 50 liters, respectively, vertical tube baffles and spiral coil. The mechanical impellers used were the 45° pitched blade turbine (PBT) and the Rushton turbine (RT). Aqueous solutions of carboxymethylcellulose (0.5%, 1.0% and 1.5%), aqueous solution of carbopol 940 (1.5%), aqueous solution of sucrose (50%) and water were used as fluids. All the experiments were conducted in batch. With the obtained data, we used the regressions to obtain the Nusselt Equation, which provided coefficient of determination values adjusted between 0.83 and 0.89 with Reynolds in the range of 20 to 405000, Prandtl in the range of 4 to 6400 and rheological index of the power law model between 0.45 and 1.00. It was observed that in the heating performed with the vertical tube baffle, the RT provided convection coefficients 20% higher when compared to the axial impeller, however the power consumption was about 66% higher in relation to the PBT. In the case of the spiral coil, the PBT promoted convection coefficients around 15% higher than the RT with 65% lower power consumption. Thus, in processes where high turbulence is not required, it is recommended to use the PBT with the spiral coil, but if the process requires significant turbulence, the RT must be used with the vertical tubular chassis. In a final analysis, the nonlinear models obtained for scaling provided errors between 11% and 20% in the prediction of rotation in the industrial tank, which are valid for Metzner and Otto (1957) modified Reynolds in the range of 20 to 4000 and for non-Newtonian pseudoplastic fluids with rheological indexes between 0.45 and 1.00.

Orientadora: Profa. Dra. Juliana Tófano de Campos Leite Toneli
Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Energia, 2014.
Os tanques com impulsores mecânicos são empregados nas indústrias químicas, petroquímicas, alimentícia, farmacêutica e mineral, como reatores químicos, diluidores, decantadores, misturadores e trocadores de calor. A transmissão de calor em tanques com agitação é realizada através das jaquetas, serpentinas helicoidais, serpentinas em espiral e chicanas tubulares verticais, sendo que existe uma carência de dados na literatura sobre a utilização das chicanas tubulares, em projetos em escala industrial. O presente estudo teve por objetivo principal comparar a transferência de calor e o consumo energético em tanques com impulsores mecânicos, axial e radial, equipados com chicanas tubulares verticais. Como objetivos específicos, o presente estudo visou determinar correlações semi-empíricas para o coeficiente convectivo no escoamento externo, em relação aos impulsores mecânicos utilizados em função dos parâmetros de similaridade Reynolds e Prandtl, e avaliar o efeito do impulsor mecânico sobre a potência consumida e a transmissão de calor. A unidade experimental consistiu, basicamente, de um tanque de acrílico com um volume útil de 50 litros, um impulsor mecânico axial, um impulsor radial tipo turbina, um motor elétrico de 2,5 hp e uma chicana tubular com 4 bancos de tubos de cobre. Os fluidos frios utilizados foram água e solução de sacarose com concentrações de 20% e 50% em massa. O fluido quente utilizado foi água à temperatura constante de 60°C e vazão de 1,2 LPM. Os ensaios foram realizados alternando as rotações na faixa de 90 a 330 RPM e a temperatura de entrada do fluido frio no intervalo de 28°C a 45°C. A potência consumida por ambos os impulsores mecânicos foi determinada a partir da técnica da medição do torque gerado no motor elétrico. O modelo obtido para a previsão do coeficiente externo de convecção, com o impulsor axial apresentou, um desvio médio de 21% e o modelo para o impulsor radial, um desvio médio de 25%. A partir dos modelos obtidos, verificou-se que o impulsor radial incrementa a transmissão de calor em 43% quando comparado com o impulsor axial. A rotação ideal para a maior transmissão de calor, durante o aquecimento das soluções, com o menor consumo de energia foi de 300 rpm. A partir das curvas simultâneas do número de potência e do número de Nusselt, conclui-se que o impulsor axial é o mais indicado para o aquecimento tendo em vista o seu baixo consumo de potência em relação ao impulsor radial.
EThe tanks with mechanical impellers are employed in chemical, petrochemical, food, pharmaceutical and mineral industries, as chemical reactors, thinners, decanters, mixers and heat exchangers. The heat transmission in tanks with agitation is performed through the jackets, helical coils, coils in spiral and vertical tubular baffles, considering that there is a lack of data in the literature on the use of tubular baffles, in industrial scale projects. The present study aimed to compare the main heat transfer and energy consumption in tanks with mechanical axial and radial impellers equipped with tubular vertical baffles. As specific objectives, this study aimed to determine correlations for convective coefficient in the external flow in relation to mechanical impellers used in function of Reynolds and Prandtl similarity parameters, and evaluate the mechanical effect on power consumption and heat transmission. The experimental unit consisted primarily of an acrylic tank with a useful volume of 50 liters, an axial mechanical and turbine type radial impeller, a 2.5 hp electric motor and a tubular chicanery with 4 banks of copper tubes. The cold fluids applied were water, and sucrose solution with concentrations of 20% and 50% by mass. The hot fluid applied was water at constant temperature of 60° C and a 1.2 LPM flow. The tests were carried out in the range of rotations by 90 to 330 RPM and the cold fluid inlet temperature in the range from 28° C to 45° C. The power consumed by both mechanical impellers was determined through the thechnique of measurement of the torque generated at electric motor. The model obtained for external coefficient prediction of convection with the axial impeller presented an average deviation of 21% and the template for the radial impeller, a standard deviation of 25%. From the models obtained, it was found that the radial impeller increases the transmission of heat in 43% when compared with the axial impeller. The ideal rotation for greater heat transfer during heating of the solutions with the lowest energy consumption amounted to 300 rpm. From the number of concurrent power curves and Nusselt number, it is concluded that the axial impeller is the most indicated for heating in view of its low power consumption compared to radial impeller.

A semi-analytical model is presented for the evaluation of the performance factor of the inlet zone of an E type shell and tube heat exchanger without leakage flows. The performance factor is defined as the ratio of dimensionless heat transfer coefficients and pressure drops of both vertical and horizontal baffle orientation and therefore facilitates the decision between horizontal and vertical baffle orientation of shell and tube heat exchangers. The model allows the calculation of the performance factor of the inlet zone as a function of the baffle cut, the shell-side Reynolds number at the inlet nozzle and the Prandtl number of the shell-side fluid. The application of the model requires the knowledge of the performance factor of water at baffle cut equal to 24% of the shell inside diameter. For the development of the model a numerical data basis is used due to the lack of experimental data for shell and tube heat exchangers with different baffle orientations. The numerical data are obtained from CFD calculations for steady state conditions within a segmentally baffled shell and tube heat exchanger following the TEMA standards. Air, water and engine oil with Prandtl numbers in the range of 0.7 to 206 are used as shell-side fluids. The semi-analytical model introduced for the performance factor predicts the CFD results with a relative absolute error less than 5%. The presented model has to be validated with further experimental data and/or numerical results which explain the effect of baffle orientation on the shell-side heat transfer coefficient and pressure drop in order to check the general applicability.

In this paper, the gas-side fluid flow distribution inside a bayonet tube heat exchanger with inner and outer fins is numerically studied. The heat exchanger is designed based on the traditional bayonet tube heat exchanger, where compact continuous plain fins and wave-like fins are mounted on the outside and inside surfaces of outer tubes, respectively, to enhance the heat transfer performance. However, gross flow maldistribution and large vortices are observed in the gas-side flow channel of baseline design. In order to improve the flow uniformity, three modified designs are proposed. Three vertical plates and two inclined plates are mounted on the inlet manifold for Model B. For the Model C, another six bending plates are mounted on the middle manifolds and three pairs of them are connected together. The Model D has a similar structure as Model C except for the two additional baffles. The results indicate that the flow distributions of Model C and D are much more uniform under different inlet Reynolds number, especially in the high inlet Reynolds number. Although the flow distribution of Model D is the best, its pressure drop is 2.6 times higher than that of Model C. Therefore, the design of Model C is the most optimized structure. Compared with the original design, the nonuniformity of Model C can be reduced by 42% while the pressure drop is almost the same under the baseline condition.