一种排气式膛压模拟装置

为了在实验室条件下简洁、高效地获得与实际相符的膛压曲线，进而开展典型结构和材料膛压载荷响应特性研究，提出了压力舱内发射药燃烧同时发射药气体由排气件排出的膛压模拟装置。结合发射药燃烧理论和等熵流动模型，建立了排气式膛压模拟过程的数学模型。基于理想气体假设，利用Fluent软件模拟泄压过程质量流量规律，并与理论结果对比，确定了流量系数。分别根据76和155 mm火炮膛压曲线特点及小型化设计原则，对模拟装置性能参数进行了优化设计。优化结果表明，获得的压力曲线的增压速率和降压速率基本满足要求，峰值压力达到300 MPa，压力大于30 MPa历时10 ms以上。验证实验结果表明:压力曲线有良好的重复性，且与理论结果一致，装置工作可靠性高；以排放发射药气体方式模拟膛压曲线是可行的。

A chamber pressure simulator with an exhaust element

In order to achieve the time-history curves of chamber pressure conveniently and efficiently at the lab-scale and further to investigate the damage patterns of typical structures and materials during transient high pressure in the chamber, a chamber pressure simulator with an exhaust element to discharge the gas generated due to the propellant combustion in the vessel was developed. A mathematical model which describes the working principle of the simulator was derived according to the propellant combustion theory and the isentropic flow model. The mass flow rate during the depressurization procedure was attained using the software Fluent on the basis of the ideal gas hypothesis, which was compared to theoretical results to determine the discharge coefficient. The performance parameters of the simulator were designed optimally based on the characteristics of time-history curves of chamber pressure for 76 mm and 155 mm guns and the miniaturization design principle. Optimization results show that pressurization and depressurization rates are satisfactory, the peak pressure is about 300 MPa and the duration when the pressure is higher than 30 MPa is longer than 10 ms. Results of verification tests present good repeatability and are coincident with theoretical results, which indicates that the simulator works with high reliability. It is feasible to simulate time-history curves of chamber pressure through exhausting propellant gas directly.