新型自激式波动射流发生装置及其射流冲击特性

A New Self-Excited Wave Jet Generator and Its Jet Impact Characteristics

为了对新型自激式波动射流发生装置及其射流冲击特性进行研究,利用Fluent软件对装置工作原理、流动及冲击特性进行数值模拟,并加工制作装置样机;通过全尺寸波动射流冲击特性试验对模拟结果进行验证,揭示了装置自激波动射流机理,得到主射流雷诺数、围压对装置性能的影响规律。研究结果表明:装置出口因附壁效应形成规律的波动射流,装置上部喷嘴与下部喷嘴的压力、流速波动基本一致;出口流速幅值受主射流雷诺数影响较大,且成正比关系;雷诺数对频率影响不大;自激式波动射流发生装置的冲击特性受围压影响较小;随着排量的提高,出口流速整体呈上升趋势,极值、幅值均与排量呈正相关;试验结果与数值模拟结果趋势相符,数值误差为8.7%,进一步验证了数值模拟方法用于瞬态射流过程预测的可行性。研究结果可为新型自激式波动射流发生装置的进一步优化提供依据。

In order to study the new self-excited wave jet generator and its jet impact characteristics,the Fluent software was used to conduct numerical simulation on the working principle,flow and impact characteristics of the device,and a prototype of the device was manufactured.Then,a full-scale wave jet impact characteristic test was conducted to verify the simulation results,revealing the self-excited wave jet mechanism of the device,and obtaining the influence law of the main jet Reynolds number and confining pressure on the device performance.The study results show that regular wave jet is formed at outlet of the device,the pressure and flow wave of the upper nozzle and the lower nozzle of the device are basically the same,the flow rate amplitude at the outlet is greatly affected by the Reynolds number of the main jet,and they are proportional to each other;the Reynolds number has little effect on the frequency,and the impact characteristics of the self-excited wave jet generator are less affected by the confining pressure;as the displacement increases,the flow rate at outlet shows an overall upward trend,and the extreme value and amplitude are positively correlated with the displacement;the test results are consistent with the trend of numerical simulation results,and the numerical error is 8.7%,which further verifies the feasibility of the numerical simulation method for the prediction of transient jet process.The study results provide a basis for further optimization and improvement of the new self-excited wave jet generator.