The modeling of inlet and exhaust systems of internal combustion engine is very important in order to evaluate the engine performance.This paper presents new pressure losses models which can be included in a one dimen...The modeling of inlet and exhaust systems of internal combustion engine is very important in order to evaluate the engine performance.This paper presents new pressure losses models which can be included in a one dimensional engine simulation code.In a first part,a CFD analysis is made in order to show the importance of the density in the modeling approach.Then,the CFD code is used,as a numerical test bench,for the pressure losses models development.These coefficients depend on the geometrical characteristics of the junction and an experimental validation is made with the use of a shock tube test bench.All the models are then included in the engine simulation code of the laboratory.The numerical calculation of unsteady compressible flow,in each pipe of the inlet and exhaust systems,is made and the calculated engine torque is compared with experimental measurements.展开更多
In order to prolong the residence time of the flow retaining in the supersonic flow, wall cavity has been widely applied in the scramjet combustor, and this affects the aerodynamic surface and imposes additional drag ...In order to prolong the residence time of the flow retaining in the supersonic flow, wall cavity has been widely applied in the scramjet combustor, and this affects the aerodynamic surface and imposes additional drag force on the hypersonic propulsion system. The two-dimensional coupled implicit Reynolds Averaged Navier-Stokes (RANS) equations and the RNG k?ε turbulent model were employed to investigate the flow fields of cavities with different geometric configurations, namely the classical rectangular, triangular and semi-circular, and the cavities with the fixed depth and length-to-depth ratio. At the same time, the drag force performances of the cavities were estimated and compared. The obtained results show that the numerical results are in very good agreement with the experimental data, and the different scales of grid make only a slight difference from the numerical results. The intensity of the trailing shock wave is much stronger than that of the leading one, and the area around the trailing edge of the cavities plays an important role in the chemical reaction in the scramjet combustor. With the fixed depth and length-to-depth ratio, the triangular cavity can strengthen the turbulent combustion in the scramjet combustor further, but impose the most additional drag force on the scramjet engine. The classical rectangular one can impose the least additional drag force on the engine, but the function of strengthening the combustion is the weakest. The influence of the semi-circular one is the moderate, but the machining process is more complex than the other two configurations.展开更多
An integrated program was established to design a combustor for a liquid rocket engine and to analyze regenerative cooling results on a preliminary design level.Properties of burnt gas from a kerosene-LOx mixture in t...An integrated program was established to design a combustor for a liquid rocket engine and to analyze regenerative cooling results on a preliminary design level.Properties of burnt gas from a kerosene-LOx mixture in the combustor and rocket performance were calculated from CEA which is the code for the calculation of chemical equilibrium.The heat transfer of regenerative cooling was analyzed by using SUPERTRAPP code for coolant properties and by one-dimensional correlations of the heat transfer coefficient from the combustor liner to the coolant.Profiles of the combustors of F-1 and RS-27A engines were designed from similar input data and the present results were compared to actual data for validation.Finally,the combustors of 30 tonf class,75 tonf class and 150 tonf class were designed from the required thrust,combustion chamber,exit pressure and mixture ratio of propellants.The wall temperature,heat flux and pressure drop were calculated for heat transfer analysis of regenerative cooling using the profiles.展开更多
文摘The modeling of inlet and exhaust systems of internal combustion engine is very important in order to evaluate the engine performance.This paper presents new pressure losses models which can be included in a one dimensional engine simulation code.In a first part,a CFD analysis is made in order to show the importance of the density in the modeling approach.Then,the CFD code is used,as a numerical test bench,for the pressure losses models development.These coefficients depend on the geometrical characteristics of the junction and an experimental validation is made with the use of a shock tube test bench.All the models are then included in the engine simulation code of the laboratory.The numerical calculation of unsteady compressible flow,in each pipe of the inlet and exhaust systems,is made and the calculated engine torque is compared with experimental measurements.
基金supported by the National Natural Science Foundation of China (Grant No. 90816027)the Excellent Graduate Student Innovative Project of the National University of Defense Technology (Grant No. B070101)+1 种基金the Hunan Provincial Foundation for Postgraduate (Grant No. 3206)the Chinese Scholarship Council (CSC) for their financial support (Grant No. 2009611036)
文摘In order to prolong the residence time of the flow retaining in the supersonic flow, wall cavity has been widely applied in the scramjet combustor, and this affects the aerodynamic surface and imposes additional drag force on the hypersonic propulsion system. The two-dimensional coupled implicit Reynolds Averaged Navier-Stokes (RANS) equations and the RNG k?ε turbulent model were employed to investigate the flow fields of cavities with different geometric configurations, namely the classical rectangular, triangular and semi-circular, and the cavities with the fixed depth and length-to-depth ratio. At the same time, the drag force performances of the cavities were estimated and compared. The obtained results show that the numerical results are in very good agreement with the experimental data, and the different scales of grid make only a slight difference from the numerical results. The intensity of the trailing shock wave is much stronger than that of the leading one, and the area around the trailing edge of the cavities plays an important role in the chemical reaction in the scramjet combustor. With the fixed depth and length-to-depth ratio, the triangular cavity can strengthen the turbulent combustion in the scramjet combustor further, but impose the most additional drag force on the scramjet engine. The classical rectangular one can impose the least additional drag force on the engine, but the function of strengthening the combustion is the weakest. The influence of the semi-circular one is the moderate, but the machining process is more complex than the other two configurations.
基金supported by the Output-oriented Project of Collaborative Research Program with Higher Education Partners of Korea Aerospace Research Insti-tute in 2009
文摘An integrated program was established to design a combustor for a liquid rocket engine and to analyze regenerative cooling results on a preliminary design level.Properties of burnt gas from a kerosene-LOx mixture in the combustor and rocket performance were calculated from CEA which is the code for the calculation of chemical equilibrium.The heat transfer of regenerative cooling was analyzed by using SUPERTRAPP code for coolant properties and by one-dimensional correlations of the heat transfer coefficient from the combustor liner to the coolant.Profiles of the combustors of F-1 and RS-27A engines were designed from similar input data and the present results were compared to actual data for validation.Finally,the combustors of 30 tonf class,75 tonf class and 150 tonf class were designed from the required thrust,combustion chamber,exit pressure and mixture ratio of propellants.The wall temperature,heat flux and pressure drop were calculated for heat transfer analysis of regenerative cooling using the profiles.
