Pub Date : 2001-11-11DOI: 10.1115/imece2001/pid-25614
S. Sami, J. Grell
Two phase flow pressure drop characteristics observed during condensation and boiling of azeotropic refrigerant mixtures R-404A (R125/R134a/R143a:44/4/52), R-407B (R32/R125/ R134a:10/70/20), R407C (R32/R125/R134a:23/25/52) and R408A (R22/R125/R143a:46/7/47) are presented in this paper. Experiments showed that for liquid Reynolds numbers higher than 3.00 E06, R-408A appears to have greater heat transfer rates than the other blends under investigation. Furthermore, it is quite evident from this data that R-407C has the highest specific pressure drop among the refrigerants under investigation.
{"title":"Study of Pressure Drop of Refrigerant Mixtures Inside Enhanced Surface Tubing","authors":"S. Sami, J. Grell","doi":"10.1115/imece2001/pid-25614","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25614","url":null,"abstract":"\u0000 Two phase flow pressure drop characteristics observed during condensation and boiling of azeotropic refrigerant mixtures R-404A (R125/R134a/R143a:44/4/52), R-407B (R32/R125/ R134a:10/70/20), R407C (R32/R125/R134a:23/25/52) and R408A (R22/R125/R143a:46/7/47) are presented in this paper.\u0000 Experiments showed that for liquid Reynolds numbers higher than 3.00 E06, R-408A appears to have greater heat transfer rates than the other blends under investigation. Furthermore, it is quite evident from this data that R-407C has the highest specific pressure drop among the refrigerants under investigation.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82845071","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/pid-25617
J. Easton
As demand for high and ultra pure water increases, enhanced performance from pretreatment systems become more and more necessary. When operated at full potential, pretreatment systems can greatly improve downstream unit processes, however many pretreatment systems become a mysterious “black box” that are often neglected. Proper training and understanding of the intricacies of pretreatment variables and constraints is a valuable resource for any system operator. This paper discusses the application of true solids contact clarification and multi-media filtration in lime softening and turbidity reduction applications. Basic mechanical and process features as well as testing, instrumentation and control parameters will be covered. Terminology and analysis techniques for optimization will be introduced. The objective of this paper is to give the plant operator the understanding necessary to optimize the effluent quality and operability of the solids contact clarifier and multi-media filter pretreatment system.
{"title":"Understanding and Operating Pretreatment Systems","authors":"J. Easton","doi":"10.1115/imece2001/pid-25617","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25617","url":null,"abstract":"\u0000 As demand for high and ultra pure water increases, enhanced performance from pretreatment systems become more and more necessary. When operated at full potential, pretreatment systems can greatly improve downstream unit processes, however many pretreatment systems become a mysterious “black box” that are often neglected. Proper training and understanding of the intricacies of pretreatment variables and constraints is a valuable resource for any system operator.\u0000 This paper discusses the application of true solids contact clarification and multi-media filtration in lime softening and turbidity reduction applications. Basic mechanical and process features as well as testing, instrumentation and control parameters will be covered. Terminology and analysis techniques for optimization will be introduced. The objective of this paper is to give the plant operator the understanding necessary to optimize the effluent quality and operability of the solids contact clarifier and multi-media filter pretreatment system.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84176714","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/pid-25616
D. Haack, K. Butcher, T. Kim, T. Lu
An overview of open cell metal foam materials with application to advanced heat exchange devices is presented. The metal foam materials considered consist of interconnected cells in a random orientation. Metal foam materials, manufacture and fabrication into complex heat exchange components are described. Experiments with flat foam panels brazed to copper sheets shows increasing heat removal effectiveness with decreasing product pore size at equivalent coolant flow rates. However, the high-pressure drop associated with flow through small pore-size material makes the use of larger pore size material more attractive.
{"title":"Novel Lightweight Metal Foam Heat Exchangers","authors":"D. Haack, K. Butcher, T. Kim, T. Lu","doi":"10.1115/imece2001/pid-25616","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25616","url":null,"abstract":"\u0000 An overview of open cell metal foam materials with application to advanced heat exchange devices is presented. The metal foam materials considered consist of interconnected cells in a random orientation. Metal foam materials, manufacture and fabrication into complex heat exchange components are described. Experiments with flat foam panels brazed to copper sheets shows increasing heat removal effectiveness with decreasing product pore size at equivalent coolant flow rates. However, the high-pressure drop associated with flow through small pore-size material makes the use of larger pore size material more attractive.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"9 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83631595","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/pid-25615
S. Beale, W. Dong, S. Zhubrin, R. Boersma
This paper presents the results of a collaborative research project of computer modeling of transport phenomena within the passages of solid-oxide fuel cells. From a mechanical design viewpoint, fuel cells may be considered to be similar to heat exchangers with internal heat generation due to ohmic heating. This is a function of load-driven factors. The thermomechanical design of the units is of paramount importance, as the reaction rates are a function of temperature, pressure, and species concentrations, i.e., the process is fully coupled. The design goal of the project is to ensure uniform flow and temperature distribution throughout the stack, to optimize performance and minimize the risk of failure. We developed computer models to predict the performance of cells and stacks of cells, so as to minimize the development of expensive experimental protypes and test rigs. The standard techniques of heat transfer and computational fluid dynamics were substantially modified to be applicable in this context. Three distinct approaches were considered. In all cases two fluids; air and fuel, each containing different chemical species were considered. The equations for fluid flow, heat and mass transfer with electro-chemical reactions occurring were discretized and solved using a finite-volume method. Detailed numerical simulations of a single cell and stacks of up to 54 cells were performed using fine three-dimensional meshes of up to 4.6 million cells. Simplified models based on a distributed resistance (porous media) analogy, and also traditional presumed flow methods used in heat exchanger and furnace design, were also employed. These latter approaches have the advantage of being readily executable on small personal computers. The three methodologies are described and compared in detail.
{"title":"Calculations of Transport Phenomena in Solid-Oxide Fuel Cells","authors":"S. Beale, W. Dong, S. Zhubrin, R. Boersma","doi":"10.1115/imece2001/pid-25615","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25615","url":null,"abstract":"\u0000 This paper presents the results of a collaborative research project of computer modeling of transport phenomena within the passages of solid-oxide fuel cells. From a mechanical design viewpoint, fuel cells may be considered to be similar to heat exchangers with internal heat generation due to ohmic heating. This is a function of load-driven factors. The thermomechanical design of the units is of paramount importance, as the reaction rates are a function of temperature, pressure, and species concentrations, i.e., the process is fully coupled. The design goal of the project is to ensure uniform flow and temperature distribution throughout the stack, to optimize performance and minimize the risk of failure.\u0000 We developed computer models to predict the performance of cells and stacks of cells, so as to minimize the development of expensive experimental protypes and test rigs. The standard techniques of heat transfer and computational fluid dynamics were substantially modified to be applicable in this context. Three distinct approaches were considered. In all cases two fluids; air and fuel, each containing different chemical species were considered. The equations for fluid flow, heat and mass transfer with electro-chemical reactions occurring were discretized and solved using a finite-volume method. Detailed numerical simulations of a single cell and stacks of up to 54 cells were performed using fine three-dimensional meshes of up to 4.6 million cells. Simplified models based on a distributed resistance (porous media) analogy, and also traditional presumed flow methods used in heat exchanger and furnace design, were also employed. These latter approaches have the advantage of being readily executable on small personal computers. The three methodologies are described and compared in detail.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"9 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78316094","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/pid-25611
Z. Haque, Z. Huque, Md. N. Jahingir
The paper shows how appropriate selection of the expression of sound speed as a function of temperature can improve the results obtained using acoustic pyrometers. Sound propagation within high temperature hydrocarbon combustion products was considered. Three different mathematical models for calculating sound speed were discussed. Results obtained using all three methods were presented. The paper observed that, it is important to consider the effects of chemical kinetics for a certain frequency range to obtain better results.
{"title":"A New Method to Improve Pyrometry Results","authors":"Z. Haque, Z. Huque, Md. N. Jahingir","doi":"10.1115/imece2001/pid-25611","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25611","url":null,"abstract":"\u0000 The paper shows how appropriate selection of the expression of sound speed as a function of temperature can improve the results obtained using acoustic pyrometers. Sound propagation within high temperature hydrocarbon combustion products was considered. Three different mathematical models for calculating sound speed were discussed. Results obtained using all three methods were presented. The paper observed that, it is important to consider the effects of chemical kinetics for a certain frequency range to obtain better results.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"73 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80038055","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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