Performance parameter analysis of pulse detonation combustors based on enthalpy and exergy consistent equivalence methodology

As a pressure-gain combustor, the pulse detonation combustor exhibits unsteady characteristics that make its performance parameters difficult to evaluate using steady-state methods. This paper proposes a parameter equivalence method based on enthalpy/exergy consistency, which, grounded in the first and second laws of thermodynamics, establishes integral conservation relations for enthalpy and exergy at the PDC outlet. The equivalent specific enthalpy and specific exergy at the outlet are obtained, enabling the calculation of equivalent total temperature and total pressure, and thus allowing for the evaluation of pressure ratio and combustion efficiency. Based on this method, the paper further theoretically analyzes how PDC operating parameters influence its performance characteristics. The results show that when the equivalence ratio varies from 0.6 to 1.6, the pressure ratio increases from 1.88 to a peak value of 2.725, while combustion efficiency reaches its maximum of approximately 90.2 % at an equivalence ratio of 0.8. As the total pressure recovery coefficient of the isolator increases from 0.4 to 1.0, the PDC's pressure ratio and combustion efficiency improve by approximately 85 % and 1 %, respectively. Compared with 10 Hz, operation at 30 Hz results in a 24.8 % increase in combustion efficiency, while the pressure ratio decreases by 17.8 %. This study, for the first time, applies an energy-conservation-based parameter equivalence method to the performance evaluation of pulse detonation combustors, and provides important theoretical support and engineering guidance for the design and optimization of pressure gain combustion systems.