Large eddy simulation of rotating channel flow with and without heat transfer is reported. The rotation axis is parallel to the spanwise direction of the parallel plate channel. An implicit finite-volume scheme was used to solve the preconditioned time-dependent filtered Navier-Stokes equations using a dynamic subgrid-scale model to account for the subgrid-scale effects. Comparisons are made with available results in the literature for isothermal rotating flows. The combined effects of rotation and heat transfer on the structure of turbulence channel flow is discussed.
{"title":"Large Eddy Simulation of Rotating Channel Flows With and Without Heat Transfer","authors":"N. Meng, R. Pletcher","doi":"10.1115/imece2000-1579","DOIUrl":"https://doi.org/10.1115/imece2000-1579","url":null,"abstract":"\u0000 Large eddy simulation of rotating channel flow with and without heat transfer is reported. The rotation axis is parallel to the spanwise direction of the parallel plate channel. An implicit finite-volume scheme was used to solve the preconditioned time-dependent filtered Navier-Stokes equations using a dynamic subgrid-scale model to account for the subgrid-scale effects. Comparisons are made with available results in the literature for isothermal rotating flows. The combined effects of rotation and heat transfer on the structure of turbulence channel flow is discussed.","PeriodicalId":221080,"journal":{"name":"Heat Transfer: Volume 5","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127727400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Steam Enhanced Extraction (SEE) process is being considered for removal of volatile organic contaminants contained in the fractured basalt rocks which lie above the Snake River aquifer at the Idaho National Engineering and Environmental Laboratory (INEEL). In this work the computer code M2NOTS (Multiphase Multi-component Non-isothermal Organic Transport Simulator) was used to simulate an experiment which tracked the movement of a steam condensation front through glass blocks separated by glass beads. The experiment was designed to represent steam injection into highly fractured basalt. For grid spacing equal to the block size heat transfer from the fractures to the blocks was severely under predicted, resulting in an over prediction of the condensation front velocity. A method was developed to accurately simulate the propagation of a steam condensation front through a fractured porous media using grid spacing equal to the block dimension. The method accounts for non-equilibrium conduction within a grid node, allowing the grid spacing to be increased well beyond the local equilibrium restriction. Simulation results compare well with the experimental results, validating the non-equilibrium model, and also indicating that M2NOTs can be effectively used to model the steam enhanced extraction process in fractured porous media.
{"title":"Numerical Modeling of Steam Injection Into Saturated Porous Media","authors":"Scott F. Kaslusky, K. Udell, G. McCreery","doi":"10.1115/imece2000-1568","DOIUrl":"https://doi.org/10.1115/imece2000-1568","url":null,"abstract":"\u0000 The Steam Enhanced Extraction (SEE) process is being considered for removal of volatile organic contaminants contained in the fractured basalt rocks which lie above the Snake River aquifer at the Idaho National Engineering and Environmental Laboratory (INEEL). In this work the computer code M2NOTS (Multiphase Multi-component Non-isothermal Organic Transport Simulator) was used to simulate an experiment which tracked the movement of a steam condensation front through glass blocks separated by glass beads. The experiment was designed to represent steam injection into highly fractured basalt. For grid spacing equal to the block size heat transfer from the fractures to the blocks was severely under predicted, resulting in an over prediction of the condensation front velocity. A method was developed to accurately simulate the propagation of a steam condensation front through a fractured porous media using grid spacing equal to the block dimension. The method accounts for non-equilibrium conduction within a grid node, allowing the grid spacing to be increased well beyond the local equilibrium restriction. Simulation results compare well with the experimental results, validating the non-equilibrium model, and also indicating that M2NOTs can be effectively used to model the steam enhanced extraction process in fractured porous media.","PeriodicalId":221080,"journal":{"name":"Heat Transfer: Volume 5","volume":"164 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116795063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Modern finite element methods implemented on parallel supercomputers promise to allow the study of three-dimensional, time-dependent continuum phenomena in many engineering systems. This paper shows several examples of the fruitful application of these approaches to bulk crystal growth systems, where strongly nonlinear coupled phenomena are important.
{"title":"Three-Dimensional Computations of Transport and Growth for Crystal Growth Systems","authors":"J. Derby, A. Yeckel","doi":"10.1115/imece2000-1586","DOIUrl":"https://doi.org/10.1115/imece2000-1586","url":null,"abstract":"\u0000 Modern finite element methods implemented on parallel supercomputers promise to allow the study of three-dimensional, time-dependent continuum phenomena in many engineering systems. This paper shows several examples of the fruitful application of these approaches to bulk crystal growth systems, where strongly nonlinear coupled phenomena are important.","PeriodicalId":221080,"journal":{"name":"Heat Transfer: Volume 5","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132389657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The hybrid finite volume/PDF Monte Carlo method has both the advantages of the finite volume method’s efficiency in solving flow fields and the PDF method’s exactness in dealing with chemical reactions. It is, therefore, increasingly used in turbulent reactive flow calculations. In order to resolve the sharp gradients of flow velocities and/or scalars, fine grids or unstructured solution -adaptive grids have to be used in the finite volume code. As a result, the calculation domain is covered by a grid system with very large variations in cell size. Such grids present a challenge for a combined PDF/Monte Carlo code. To date, PDF calculations have generally been carried out with large cells, which assure that each cell has a statistically meaningful number of particles. Smaller cells would lead to smaller numbers of particles and correspondingly larger statistical errors. In this paper, a particle tracing scheme with adaptive time step and particle splitting and combination is developed, which allows the PDF/Monte Carlo code to use any grid that is constructed in the finite volume code. This relaxation of restrictions on the grid makes it possible to couple PDF/Monte Carlo methods to all popular commercial CFD codes and, consequently, extend existing CFD codes’ capability to simulate turbulent reactive flow in a more accurate way. To illustrate the solution procedure, a PDF/ Monte Carlo code is combined with FLUENT to solve a turbulent diffusion combustion problem in an axisymmetric channel.
有限体积/PDF混合蒙特卡罗方法具有有限体积法求解流场的效率和PDF法处理化学反应的准确性的优点。因此，它越来越多地用于湍流反应流的计算。为了解决流速和/或标量的急剧梯度，必须在有限体积代码中使用精细网格或非结构化解自适应网格。结果，计算域被网格系统覆盖，网格大小变化很大。这样的网格对PDF/Monte Carlo代码的组合提出了挑战。迄今为止，PDF计算通常使用大单元进行，以确保每个单元具有统计上有意义的粒子数量。细胞越小，粒子数量越少，相应的统计误差也越大。本文提出了一种具有自适应时间步长和粒子分裂与组合的粒子跟踪方案，使PDF/蒙特卡罗码能够使用有限体积码中构造的任意网格。这种对网格限制的放松使得PDF/Monte Carlo方法与所有流行的商业CFD代码相结合成为可能，从而扩展了现有CFD代码以更准确的方式模拟湍流反应流的能力。为了说明求解过程，将PDF/ Monte Carlo代码与FLUENT相结合，求解轴对称通道中的湍流扩散燃烧问题。
{"title":"A Hybrid Finite Volume/PDF Monte Carlo Method to Capture Sharp Gradients in Unstructured Grids","authors":"Genong Li, M. Modest","doi":"10.1115/imece2000-1580","DOIUrl":"https://doi.org/10.1115/imece2000-1580","url":null,"abstract":"\u0000 The hybrid finite volume/PDF Monte Carlo method has both the advantages of the finite volume method’s efficiency in solving flow fields and the PDF method’s exactness in dealing with chemical reactions. It is, therefore, increasingly used in turbulent reactive flow calculations. In order to resolve the sharp gradients of flow velocities and/or scalars, fine grids or unstructured solution -adaptive grids have to be used in the finite volume code. As a result, the calculation domain is covered by a grid system with very large variations in cell size. Such grids present a challenge for a combined PDF/Monte Carlo code. To date, PDF calculations have generally been carried out with large cells, which assure that each cell has a statistically meaningful number of particles. Smaller cells would lead to smaller numbers of particles and correspondingly larger statistical errors. In this paper, a particle tracing scheme with adaptive time step and particle splitting and combination is developed, which allows the PDF/Monte Carlo code to use any grid that is constructed in the finite volume code. This relaxation of restrictions on the grid makes it possible to couple PDF/Monte Carlo methods to all popular commercial CFD codes and, consequently, extend existing CFD codes’ capability to simulate turbulent reactive flow in a more accurate way. To illustrate the solution procedure, a PDF/ Monte Carlo code is combined with FLUENT to solve a turbulent diffusion combustion problem in an axisymmetric channel.","PeriodicalId":221080,"journal":{"name":"Heat Transfer: Volume 5","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121698287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents numerical results for laminar heat transfer and turbulent flow past a backward-facing step channel with and without a porous insert. The effects of thickness and permeability of the inserts on flow pattern and heat transfer features are assessed. It is found that for some combinations of thickness and permeability, the recirculating bubble right after the step is completely suppressed, improving the heat transfer characteristics for the lower wall.
{"title":"Heat Transfer in Suddenly Expanded Flow in a Channel With Porous Inserts","authors":"Francisco D. Rocamora, M. D. de Lemos","doi":"10.1115/imece2000-1576","DOIUrl":"https://doi.org/10.1115/imece2000-1576","url":null,"abstract":"\u0000 This paper presents numerical results for laminar heat transfer and turbulent flow past a backward-facing step channel with and without a porous insert. The effects of thickness and permeability of the inserts on flow pattern and heat transfer features are assessed. It is found that for some combinations of thickness and permeability, the recirculating bubble right after the step is completely suppressed, improving the heat transfer characteristics for the lower wall.","PeriodicalId":221080,"journal":{"name":"Heat Transfer: Volume 5","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132150237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is well known that moist fire protection materials show good fire resistance characteristics. For this reason, these materials are usually made of mixtures of cement mortar and high-water content materials such as silica gels or moist perlites. The latent heat of water plays an important role in the resistance of heat propagation in these materials. In this study, the thermal conductivity of mixtures of perlite-mortar and super-absorbent polymer gel to increase its water storage capacity, were measured. Also, the water content of the test materials was measured. Using the measured thermal properties of such fire protection materials, the numerical simulation for the fire resistant test were conducted. The effects of mixing ratio of the gels and the perlite-mortar on the fire resistance characteristics are discussed.
{"title":"Fire Resistance Characteristics of Fire Protection Materials With High-Water Content","authors":"Y. Asako, T. Otaka, Y. Yamaguchi","doi":"10.1115/imece2000-1557","DOIUrl":"https://doi.org/10.1115/imece2000-1557","url":null,"abstract":"\u0000 It is well known that moist fire protection materials show good fire resistance characteristics. For this reason, these materials are usually made of mixtures of cement mortar and high-water content materials such as silica gels or moist perlites. The latent heat of water plays an important role in the resistance of heat propagation in these materials. In this study, the thermal conductivity of mixtures of perlite-mortar and super-absorbent polymer gel to increase its water storage capacity, were measured. Also, the water content of the test materials was measured. Using the measured thermal properties of such fire protection materials, the numerical simulation for the fire resistant test were conducted. The effects of mixing ratio of the gels and the perlite-mortar on the fire resistance characteristics are discussed.","PeriodicalId":221080,"journal":{"name":"Heat Transfer: Volume 5","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128769223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A combined theoretical and experimental thermal analysis is conducted on the oil flow between the plates of a wet clutch during an extended slip engagement. An analytical model, using the separation of variables technique, is developed to simulate the temperature rise due to the non-conservative friction and relative motion between the steel plates and friction plates of the clutch. A three-dimensional numerical heat transfer and fluid flow model was developed to calculate the velocity and temperature profiles in the oil groove channel. Typical velocity profiles and temperature contours plots are demonstrated. Friction factor and Nusselt number are presented as functions of axial position. The experiment performed included a wet clutch instrumented with thermocouples and installed in a power-shift transmission where the temperature rise during one clutch engagement was measured. The total energy is then estimated by accounting for system inertia, torque and rotating speeds. Finally, the inlet, outlet temperature rises and the averaged Nusselt number of the oil groove are also presented.
{"title":"Thermal Analysis of Lubricating Oil Flow Within a Wet-Disk Clutch","authors":"T. Jen, D. Nĕmec̆ek","doi":"10.1115/imece2000-1571","DOIUrl":"https://doi.org/10.1115/imece2000-1571","url":null,"abstract":"\u0000 A combined theoretical and experimental thermal analysis is conducted on the oil flow between the plates of a wet clutch during an extended slip engagement. An analytical model, using the separation of variables technique, is developed to simulate the temperature rise due to the non-conservative friction and relative motion between the steel plates and friction plates of the clutch. A three-dimensional numerical heat transfer and fluid flow model was developed to calculate the velocity and temperature profiles in the oil groove channel. Typical velocity profiles and temperature contours plots are demonstrated. Friction factor and Nusselt number are presented as functions of axial position. The experiment performed included a wet clutch instrumented with thermocouples and installed in a power-shift transmission where the temperature rise during one clutch engagement was measured. The total energy is then estimated by accounting for system inertia, torque and rotating speeds. Finally, the inlet, outlet temperature rises and the averaged Nusselt number of the oil groove are also presented.","PeriodicalId":221080,"journal":{"name":"Heat Transfer: Volume 5","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124333584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A re-meshing free algorithm is presented for optimizing the size and shape of chills in a sand casting process. The heat conduction in each chill is assumed to be one-dimensional normal to its contact surface. The chill is removed from the casting layout and replaced with heat fluxes applied on the associated mould and casting interfaces. The change in size and shape of the chill is modeled by moving the borders of the interface contact regions. A change in thickness of the chill is also included using a parameter which controls the magnitude of the interface heat fluxes and implies the thermal capacity of the chill. The model is linked to an optimization tool to search for the optimum set of dimensions of the chill that produces a prescribed directional cooling in the casting. A test case is solved to demonstrate the capability of the proposed algorithm in optimizing chill design in complex geometries.
{"title":"Optimum Design of Chills in the Sand Casting Process","authors":"M. Manzari, D. Gethin, R. Lewis","doi":"10.1115/imece2000-1584","DOIUrl":"https://doi.org/10.1115/imece2000-1584","url":null,"abstract":"\u0000 A re-meshing free algorithm is presented for optimizing the size and shape of chills in a sand casting process. The heat conduction in each chill is assumed to be one-dimensional normal to its contact surface. The chill is removed from the casting layout and replaced with heat fluxes applied on the associated mould and casting interfaces. The change in size and shape of the chill is modeled by moving the borders of the interface contact regions. A change in thickness of the chill is also included using a parameter which controls the magnitude of the interface heat fluxes and implies the thermal capacity of the chill. The model is linked to an optimization tool to search for the optimum set of dimensions of the chill that produces a prescribed directional cooling in the casting. A test case is solved to demonstrate the capability of the proposed algorithm in optimizing chill design in complex geometries.","PeriodicalId":221080,"journal":{"name":"Heat Transfer: Volume 5","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126856984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A phenomenological model based on the use of multiple zones is described and compared with other experimental and analytical work. This multizone model is used to examine the effect on emissions of increasing the oxygen concentration in the intake air of a compression-ignition, direct-injection engine. It is concluded that O2-enriched air could only be useful if combined with other modifications such as auxiliary gas injection, split injection, and exhaust gas recirculation.
{"title":"The Use of a Multizone Model for Prediction of Soot and NOx Emission in a D.I. Diesel Engine as a Function of Intake Air O2 Content","authors":"Z. Gao, W. Schreiber","doi":"10.1115/imece2000-1565","DOIUrl":"https://doi.org/10.1115/imece2000-1565","url":null,"abstract":"\u0000 A phenomenological model based on the use of multiple zones is described and compared with other experimental and analytical work. This multizone model is used to examine the effect on emissions of increasing the oxygen concentration in the intake air of a compression-ignition, direct-injection engine. It is concluded that O2-enriched air could only be useful if combined with other modifications such as auxiliary gas injection, split injection, and exhaust gas recirculation.","PeriodicalId":221080,"journal":{"name":"Heat Transfer: Volume 5","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128834915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A theoretical and experimental study of the temporal development of unsteady round nonbuoyant turbulent jets (starting jets) and puffs (interrupted jets) is described, limited to sources in still and unstratified environments. The experiments involved dye-containing fresh water sources injected vertically downward into fresh water within a large windowed tank with injector passage length/diameter ratios of 50. Time-resolved video images of the flows were obtained using a CCD camera. Test conditions were as follows: jet exit diameters of 3.2–12.7 mm, jet exit Reynolds numbers of 1450–11700, volume of injected fluid for puffs up to 80 passage diameters long, and penetration lengths up to 100 source diameters. Near-source behavior varied significantly with source properties but the flows generally became turbulent near the jet exit with self-preserving behavior observed at distances greater than 20–30 source diameters from the source. Within the self-preserving region, both the normalized streamwise penetration distance and the normalized maximum flow radius varied as functions of time to the following powers, in agreement with estimates for self-preserving turbulent flows: 1/2 for starting nonbuoyant jets and 1/4 for nonbuoyant puffs.
{"title":"Structure and Mixing Properties of Unsteady Round Nonbuoyant Turbulent Jets and Puffs in Still Gases","authors":"R. Sangras, G. Faeth","doi":"10.1115/imece2000-1558","DOIUrl":"https://doi.org/10.1115/imece2000-1558","url":null,"abstract":"\u0000 A theoretical and experimental study of the temporal development of unsteady round nonbuoyant turbulent jets (starting jets) and puffs (interrupted jets) is described, limited to sources in still and unstratified environments. The experiments involved dye-containing fresh water sources injected vertically downward into fresh water within a large windowed tank with injector passage length/diameter ratios of 50. Time-resolved video images of the flows were obtained using a CCD camera. Test conditions were as follows: jet exit diameters of 3.2–12.7 mm, jet exit Reynolds numbers of 1450–11700, volume of injected fluid for puffs up to 80 passage diameters long, and penetration lengths up to 100 source diameters. Near-source behavior varied significantly with source properties but the flows generally became turbulent near the jet exit with self-preserving behavior observed at distances greater than 20–30 source diameters from the source. Within the self-preserving region, both the normalized streamwise penetration distance and the normalized maximum flow radius varied as functions of time to the following powers, in agreement with estimates for self-preserving turbulent flows: 1/2 for starting nonbuoyant jets and 1/4 for nonbuoyant puffs.","PeriodicalId":221080,"journal":{"name":"Heat Transfer: Volume 5","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117042747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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