{"title":"Numerical Simulation of NO Production in Air-Staged Pulverized Coal Fired Furnace~!2009-10-07~!2009-11-11~!2010-04-16~!","authors":"R. Straka, M. Beneš","doi":"10.2174/1874396X01004020027","DOIUrl":"https://doi.org/10.2174/1874396X01004020027","url":null,"abstract":"We describe behavior of the air-coal mixture using the Navier-Stokes equations for the mixture of air and coal particles, accompanied by a turbulence model. The undergoing chemical reactions are described by the Arrhenian kinetics (reaction rate proportional to RT E e ). We also consider the heat transfer via conduction and radiation. The system of PDEs is discretized using the finite volume method (FVM) and an advection upstream splitting method as the Riemann solver. The resulting ODEs are solved using the 4th-order Runge-Kutta method. Simulation results for typical power production level are presented together with the air-staging impact on NO production.","PeriodicalId":238681,"journal":{"name":"The Open Thermodynamics Journal","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121136796","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}
{"title":"Pulverised-Coal Combustion with Staged Air Introduction: CFD Analysis with Different Thermal Radiation Methods~!2009-08-21~!2009-10-13~!2010-04-16~!","authors":"R. Filkoski","doi":"10.2174/1874396X01004020002","DOIUrl":"https://doi.org/10.2174/1874396X01004020002","url":null,"abstract":"Combustion chamber designers endeavour to achieve optimum operating conditions that give maximum combustion efficiency, together with minimum pollutant formation rate. Modelling of fossil fuel utility boilers has reached a remarkable development in recent years. Particularly, the application of computational fluid dynamics (CFD) modelling technology and other advanced mathematical methods offer opportunities for analysis, optimisation and options examination in order to increase the overall efficiency of the energy facilities. The main purpose of the present study was to investigate how the results obtained with two radiative heat transfer methods, the P1 approximation method and the discrete ordinates (DO) method, fit temperature field in a boiler furnace on pulverised coal, with implemented over-fire air (OFA) ports. The overall framework of the CFD modelling approach is described. The numerical modelling results for boiler baseline operating conditions are compared with a test matrix of local temperature measurements. An accuracy analysis of the P1 and DO methods is done on a basis of a comparison between the numerically obtained and measured temperature profiles.","PeriodicalId":238681,"journal":{"name":"The Open Thermodynamics Journal","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134404658","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}
{"title":"Hot Topic: [Numerical analysis of heat and mass transfer in energy conversion systems (Guest Editor: Srdjan Belosevic)]","authors":"Srđan V. Belošević","doi":"10.2174/1874396X01004010001","DOIUrl":"https://doi.org/10.2174/1874396X01004010001","url":null,"abstract":"","PeriodicalId":238681,"journal":{"name":"The Open Thermodynamics Journal","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125459224","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}
{"title":"Thermal Product of Fast Response Temperature Sensors for Transient Heat Transfer Applications with Numerically Determined Surface Heat Flux History~!2009-09-06~!2009-11-10~!2010-04-16~!","authors":"H. Mohammed, H. Salleh, M. Yusoff","doi":"10.2174/1874396X01004020036","DOIUrl":"https://doi.org/10.2174/1874396X01004020036","url":null,"abstract":"A dynamic calibration technique for evaluating the thermal product values of different scratched temperature sensors is presented. These sensors have renewable junction, fast response time and it can be used for transient heat transfer measurements in hypersonic vehicles. Two types of scratch were used, mainly abrasive papers with different grit sizes and scalpel blades with different thicknesses to form the sensor junction. The effect of scratch technique on the sensor’s thermal product is investigated. The sensors were tested in shock tube facility at different operating conditions. It was observed that the thermal product of a particular sensor depends on the Mach number, surface junction scratch technique, junction location as well as on the enthalpy conditions. It was also noticed that using scalpel blade technique with a particular blade size gives consistent thermal product values. Thus, it does not require an individual calibration. However, for sensors whose junction created using abrasive paper technique with different grit sizes, a calibration for each sensor is likely to be needed. The present results have provided useful and practical data for thermal product values for different scratched temperature sensors. These data are beneficial to the experimentalists in the field and it can be used for accurate transient heat transfer rate determination. Furthermore, the present calibration technique has shown that the response time of these sensors is on the order of microseconds (less than 50 μs) and it has a rise time less than 0.3 μs. A numerical technique was used in the calculation of the heat transfer rate by developing a MATLAB routine to obtain the transient heat flux history from the measured surface temperatures history.","PeriodicalId":238681,"journal":{"name":"The Open Thermodynamics Journal","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129210669","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}
{"title":"Pulverised-Coal Combustion with Staged Air Introduction: CFD Analysis with Different Thermal Radiation Methods","authors":"R. Filkoski","doi":"10.2174/1874396X01004010002","DOIUrl":"https://doi.org/10.2174/1874396X01004010002","url":null,"abstract":"Combustion chamber designers endeavour to achieve optimum operating conditions that give maximum com- bustion efficiency, together with minimum pollutant formation rate. Modelling of fossil fuel utility boilers has reached a remarkable development in recent years. Particularly, the application of computational fluid dynamics (CFD) modelling technology and other advanced mathematical methods offer opportunities for analysis, optimisation and options examina- tion in order to increase the overall efficiency of the energy facilities. The main purpose of the present study was to inves- tigate how the results obtained with two radiative heat transfer methods, the P1 approximation method and the discrete ordinates (DO) method, fit temperature field in a boiler furnace on pulverised coal, with implemented over-fire air (OFA) ports. The overall framework of the CFD modelling approach is described. The numerical modelling results for boiler baseline operating conditions are compared with a test matrix of local temperature measurements. An accuracy analysis of the P1 and DO methods is done on a basis of a comparison between the numerically obtained and measured temperature profiles.","PeriodicalId":238681,"journal":{"name":"The Open Thermodynamics Journal","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132683061","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}
{"title":"Thermal Product of Fast Response Temperature Sensors for Transient Heat Transfer Applications with Numerically Determined Surface Heat Flux History","authors":"H. Mohammed, H. Salleh, M. Yusoff","doi":"10.2174/1874396X01004010036","DOIUrl":"https://doi.org/10.2174/1874396X01004010036","url":null,"abstract":"A dynamic calibration technique for evaluating the thermal product values of different scratched temperature sensors is presented. These sensors have renewable junction, fast response time and it can be used for transient heat trans- fer measurements in hypersonic vehicles. Two types of scratch were used, mainly abrasive papers with different grit sizes and scalpel blades with different thicknesses to form the sensor junction. The effect of scratch technique on the sensor's thermal product is investigated. The sensors were tested in shock tube facility at different operating conditions. It was ob- served that the thermal product of a particular sensor depends on the Mach number, surface junction scratch technique, junction location as well as on the enthalpy conditions. It was also noticed that using scalpel blade technique with a par- ticular blade size gives consistent thermal product values. Thus, it does not require an individual calibration. However, for sensors whose junction created using abrasive paper technique with different grit sizes, a calibration for each sensor is likely to be needed. The present results have provided useful and practical data for thermal product values for different scratched temperature sensors. These data are beneficial to the experimentalists in the field and it can be used for accurate transient heat transfer rate determination. Furthermore, the present calibration technique has shown that the response time of these sensors is on the order of microseconds (less than 50 μs) and it has a rise time less than 0.3 μs. A numerical tech- nique was used in the calculation of the heat transfer rate by developing a MATLAB routine to obtain the transient heat flux history from the measured surface temperatures history.","PeriodicalId":238681,"journal":{"name":"The Open Thermodynamics Journal","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114405289","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}
{"title":"Numerical Simulation of NO Production in Air-Staged Pulverized Coal Fired Furnace","authors":"R. Straka, M. Beneš","doi":"10.2174/1874396X01004010027","DOIUrl":"https://doi.org/10.2174/1874396X01004010027","url":null,"abstract":"We describe behavior of the air-coal mixture using the Navier-Stokes equations for the mixture of air and coal particles, accompanied by a turbulence model. The undergoing chemical reactions are described by the Arrhenian kinetics (reaction rate proportional to RT E e ). We also consider the heat transfer via conduction and radiation. The system of PDEs is discretized using the finite volume method (FVM) and an advection upstream splitting method as the Riemann solver. The resulting ODEs are solved using the 4th-order Runge-Kutta method. Simulation results for typical power production level are presented together with the air-staging impact on NO production.","PeriodicalId":238681,"journal":{"name":"The Open Thermodynamics Journal","volume":"1993 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125537836","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}
{"title":"Heat Transfer and Fluid Flows in Gas Springs","authors":"U. Lekic, J. Kok","doi":"10.2174/1874396X01004010013","DOIUrl":"https://doi.org/10.2174/1874396X01004010013","url":null,"abstract":"Thermodynamical processes and fluid mechanics phenomena occurring in an unlubricated piston-cylinder gas spring are investigated. Existing instantaneous heat transfer correlations are not applicable to the piston-cylinder compressed volumes. Accurate prediction of the transient thermal properties, heat transfer and fluid flows for the high performance, tight tolerance and lubricant-free gas compressors (e.g. cryo-cooling industry) is of high industrial importance. Research is here done with the use of ANSYS CFX finite-volume numerical package, modelling the closed fluid domain in a valveless non-lubricated one-piston-cylinder gas spring. Obtained numerically simulated values are compared to experimentally measured pressure and heat-flux data; very good agreement is observed. Broad discussion and conclusions with regard to thermodynamic and fluid-flow phenomena occurring are presented.","PeriodicalId":238681,"journal":{"name":"The Open Thermodynamics Journal","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128263808","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}
{"title":"Modeling Approaches to Predict Biomass Co-firing with Pulverized Coal","authors":"Srđan V. Belošević","doi":"10.2174/1874396X01004010050","DOIUrl":"https://doi.org/10.2174/1874396X01004010050","url":null,"abstract":"","PeriodicalId":238681,"journal":{"name":"The Open Thermodynamics Journal","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129297370","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}
{"title":"The Nu Number Behavior on Micro-tube Heat Transfer and Fluid Flow of Dielectric Fluid","authors":"D. Lelea, A. Cioabla, I. Laza, L. Mihon","doi":"10.2174/1874396X00903010038","DOIUrl":"https://doi.org/10.2174/1874396X00903010038","url":null,"abstract":"The numerical modeling of the microchannel heat transfer and fluid flow was analyzed to estimate the thermal behavior of the dielectric fluids with emphasize on Nu number behavior. The geometry of a model is the same as in (Lelea et al., 2004). The diameters of the tube were Di /Do=125.4/300 μm, the total length L=70 mm, Q=0.75 W and only a portion of the tube was heated. The laminar and stationary regime was considered with variable fluid properties. Besides, two different heat flux directions are considered: heating and cooling.","PeriodicalId":238681,"journal":{"name":"The Open Thermodynamics Journal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128286241","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}