Research On The Design Of A New Cooling Cycle For Scramjet Based On Rankine Cycle

In this dissertation,a cooling cycle system for scramjet is designed by theoretical analysis and numerical calculation.The influencing factors of cooling cycle system performance are studied,and the optimal cooling cycle parameters are obtained.A new cooling cycle system for scramjet is designed based on Rankine cycle.Based on the thermodynamic analysis of ideal Rankine cycle,the thermodynamic analysis and calculation of the designed cooling cycle were carried out,and the calculation methods of working fluid parameters and system operation parameters for each process of the cooling cycle are obtained.Then,the exergy analysis is adopted to study the exergy change problem of cooling cycle system,and the calculation method of exergy loss and exergy efficiency is obtained.On this basis,the performance of the cooling cycle system is characterized by the cycle thermal efficiency.In terms of thermal stability,flow and heat transfer,safety and environmental protection,several working fluids for cooling cycle are compared,and the effects of different working fluids on the performance of cooling cycle system are analyzed and compared.Take these factors into account,water is choosed as the working fluid of cooling cycle.The effect of working parameters and operating parameters on cycle performance in cooling cycle system is studied.The cycle thermal efficiency decreases with the increase of kerosene outlet temperature,decreases with the increase of system expansion ratio and increases with the increase of system temperature increment ratio.The effects of different factors on the system’s exergy loss and exergy efficiency are studied.And we have gotten the variation of exergy loss and exergy efficiency with the maximum temperature of water steam in the outlet of cooling channels,the system expansion ratio and kerosene flow rate in the cooling cycle.Based on the comprehensive theoretical analysis,the working medium parameters and operation parameters of the circulating system with the best performance are obtained by numerical calculation.