A cogeneration plant can run at off-design due to change of load demand or ambient conditions. The cogeneration considered for this study is gas turbine based engine consists of variable stator vanes （VSVs） compress...A cogeneration plant can run at off-design due to change of load demand or ambient conditions. The cogeneration considered for this study is gas turbine based engine consists of variable stator vanes （VSVs） compressor that are re-staggered for loads greater than 50% to maintain the gas turbine exhaust gas temperature at the set value. In order to evaluate the exergetic performance of the cogeneration, exergy model of each cogeneration component is formulated. A 4.2 MW gas turbine based cogeneration plant is analysed for a wide range of part load operations including the effect of VSVs modulation. For loads less than 50%, the major exergy destruction contributors are the combustor and the loss with the stack gas. At full load, the exergy destructions in the combustor, turbine, heat recovery, compressor and the exergy loss with stack gas are 63.7, 14.1, 11.5, 5.7, and 4.9%, respectively. The corresponding first and second law cogeneration efficiencies are 78.5 and 45%, respectively. For comparison purpose both the first and second law efticiencies of each component are represented together. This analysis would help to identify the equipment where the potential for performance improvement is high, and trends which may aid in the design of future plants.展开更多
This paper presents a method to acquire runtime distribution ratio of building air conditioning system under part load condition (part load coefficient of system) through practical energy consumption data. By utilizin...This paper presents a method to acquire runtime distribution ratio of building air conditioning system under part load condition (part load coefficient of system) through practical energy consumption data. By utilizing monthly energy consumption data of the entire year as the analysis object,this paper identifies data distribution,verifies distribution characteristics and analyzes distribution probability density for the issue of running time distribution ratio of air conditioning system in part load zones in the whole operation period,thus providing a basic calculation basis for an overall analysis of energy efficiency of air conditioning system. In view of the general survey of public building energy consumption carried by the government of Chongqing,this paper takes the governmental office building as an example,the part load ratio coefficient corresponding to practical running of air conditioning system of governmental office building in Chongqing is obtained by utilizing the above probability analysis and the solving method of probability density function. By utilizing the ratio coefficient obtained using this method,the part load coefficient with any running ratio of air conditioning system can be obtained according to the requirement of analysis,which can be used in any load ratio for analyzing running energy efficiency of air conditioning system.展开更多
The deformation characters and load status of the blank＇s potential fracture zone are analyzed at the moment when blank is approaching to punch comer in drawing process of cone shape part. Based on tension instabilit...The deformation characters and load status of the blank＇s potential fracture zone are analyzed at the moment when blank is approaching to punch comer in drawing process of cone shape part. Based on tension instability theory, the formula for calculating fracture limit load of cone shape part in drawing process is derived. Also, the formula is analyzed and verified by experiment.展开更多
Gas turbine power units,as an effective way to cope with the severe challenge of renewable energy accommodation in power grids,arouse the interest of power enterprises in the deep peak-load regulation performance.Two ...Gas turbine power units,as an effective way to cope with the severe challenge of renewable energy accommodation in power grids,arouse the interest of power enterprises in the deep peak-load regulation performance.Two common alternative load-control strategies including constant turbine inlet temperature(TIT)and constant turbine exhaust temperature(TET)regulations were taken into consideration.To comparatively investigate the part-load performance under these strategies,both mathematical and physical models were set up successively to serve as a validation and complementary to each other.For the mathematical model of compressor with inlet guide vane(IGV),combustor and turbine,stage-stacking method based on blade average geometric parameter,energy conservation and turbine stage model were adopted respectively.For the physical model,design and off-design analysis were carried out based on GT PRO and THERMOFLEX respectively.The simulation result of mathematical model validated the reliability of the physical model.Based on this,the influence of ambient temperature and different load-regulating strategies on the off-design performance of gas turbine power units was studied in THERMOFLEX.The results in the case of a PG 9351FA gas turbine show that the ambient temperature has a great impact on system performance,i.e.,every 5℃ increase in the ambient temperature produces a reduction of 3.7%in the relative full-load output and 1.1%in the relative efficiency respectively;when the gas turbine operates under constant TIT strategy,TET starts to rise till it reaches the maximum allowable value with the load rate decreasing,and IGV keeps at the minimum angle with both TIT and TET decreasing when the load rate is lower than 65%;when the gas turbine operates under constant TET strategy,TIT drops slightly at load rate of above 60%while both TIT and TET evidently decrease below 60%load rate operating along the constant corrected speed line at the minimum allowable IGV opening;gas turbine effi-ciency is greatly affected by load rate and the performance degradation is more obvious especially in lower load rate regions;constant TET strategy is superior in the operating efficiency to constant TIT strategy under part-load conditions.展开更多
文摘A cogeneration plant can run at off-design due to change of load demand or ambient conditions. The cogeneration considered for this study is gas turbine based engine consists of variable stator vanes （VSVs） compressor that are re-staggered for loads greater than 50% to maintain the gas turbine exhaust gas temperature at the set value. In order to evaluate the exergetic performance of the cogeneration, exergy model of each cogeneration component is formulated. A 4.2 MW gas turbine based cogeneration plant is analysed for a wide range of part load operations including the effect of VSVs modulation. For loads less than 50%, the major exergy destruction contributors are the combustor and the loss with the stack gas. At full load, the exergy destructions in the combustor, turbine, heat recovery, compressor and the exergy loss with stack gas are 63.7, 14.1, 11.5, 5.7, and 4.9%, respectively. The corresponding first and second law cogeneration efficiencies are 78.5 and 45%, respectively. For comparison purpose both the first and second law efticiencies of each component are represented together. This analysis would help to identify the equipment where the potential for performance improvement is high, and trends which may aid in the design of future plants.
基金Project(50838009) supported by the National Natural Science Foundation of ChinaProjects(2006BAJ02A09,2006BAJ02A13-4) supported by the National Key Technologies R & D Program of ChinaProject(CSTC,2008AB7110) supported by the Key Technologies R & D Programme of Chongqing,China
文摘This paper presents a method to acquire runtime distribution ratio of building air conditioning system under part load condition (part load coefficient of system) through practical energy consumption data. By utilizing monthly energy consumption data of the entire year as the analysis object,this paper identifies data distribution,verifies distribution characteristics and analyzes distribution probability density for the issue of running time distribution ratio of air conditioning system in part load zones in the whole operation period,thus providing a basic calculation basis for an overall analysis of energy efficiency of air conditioning system. In view of the general survey of public building energy consumption carried by the government of Chongqing,this paper takes the governmental office building as an example,the part load ratio coefficient corresponding to practical running of air conditioning system of governmental office building in Chongqing is obtained by utilizing the above probability analysis and the solving method of probability density function. By utilizing the ratio coefficient obtained using this method,the part load coefficient with any running ratio of air conditioning system can be obtained according to the requirement of analysis,which can be used in any load ratio for analyzing running energy efficiency of air conditioning system.
基金This project is supported by Doctoral Education Foundation of Ministry ofEducation of China (No.96021602).
文摘The deformation characters and load status of the blank＇s potential fracture zone are analyzed at the moment when blank is approaching to punch comer in drawing process of cone shape part. Based on tension instability theory, the formula for calculating fracture limit load of cone shape part in drawing process is derived. Also, the formula is analyzed and verified by experiment.
基金This work was supported by Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization(2013A061401005)by Guangdong Basic and Applied Basic Research Foundation(2020A1515011103)by research fund from Guangzhou Development Group Co.,Ltd.
文摘Gas turbine power units,as an effective way to cope with the severe challenge of renewable energy accommodation in power grids,arouse the interest of power enterprises in the deep peak-load regulation performance.Two common alternative load-control strategies including constant turbine inlet temperature(TIT)and constant turbine exhaust temperature(TET)regulations were taken into consideration.To comparatively investigate the part-load performance under these strategies,both mathematical and physical models were set up successively to serve as a validation and complementary to each other.For the mathematical model of compressor with inlet guide vane(IGV),combustor and turbine,stage-stacking method based on blade average geometric parameter,energy conservation and turbine stage model were adopted respectively.For the physical model,design and off-design analysis were carried out based on GT PRO and THERMOFLEX respectively.The simulation result of mathematical model validated the reliability of the physical model.Based on this,the influence of ambient temperature and different load-regulating strategies on the off-design performance of gas turbine power units was studied in THERMOFLEX.The results in the case of a PG 9351FA gas turbine show that the ambient temperature has a great impact on system performance,i.e.,every 5℃ increase in the ambient temperature produces a reduction of 3.7%in the relative full-load output and 1.1%in the relative efficiency respectively;when the gas turbine operates under constant TIT strategy,TET starts to rise till it reaches the maximum allowable value with the load rate decreasing,and IGV keeps at the minimum angle with both TIT and TET decreasing when the load rate is lower than 65%;when the gas turbine operates under constant TET strategy,TIT drops slightly at load rate of above 60%while both TIT and TET evidently decrease below 60%load rate operating along the constant corrected speed line at the minimum allowable IGV opening;gas turbine effi-ciency is greatly affected by load rate and the performance degradation is more obvious especially in lower load rate regions;constant TET strategy is superior in the operating efficiency to constant TIT strategy under part-load conditions.
