The flow characteristics of injectors with oscillations play a significant role in the mechanism of combustion instability. And combustion instability reduces engine reliability. Therefore, an efficient VOF-to-DPM model-based method is proposed to evaluate the effect of inlet mass flow rate oscillation on the injectors in liquid rocket engines. In this method, the VOF-to-DPM model, which can portray the complete spray process with less computational cost than the VOF method, is adopted to simulate the whole spray process of the injector under oscillations. The proposed method is first verified by the reported simulation work. Then, it is applied to study the flow characteristics (response and spray characteristics) of the simplex swirl injector under different inlet mass flow rate oscillations. The result of the proposed method indicates that the simplex swirl injector is sensitive to the oscillation of 200–300 Hz, which is consistent with the reported experimental work. Additionally, inlet oscillation frequency dominantly increases the phase difference while frequency and amplitude jointly determine the amplification or attenuation of the outlet mass flow. The injector with 250 Hz has a higher velocity of downstream recirculation and smaller droplets than other oscillation frequencies, which may provoke combustion instability. The numerical results are beneficial to injector design and reduce the possibility of combustion instability by active regulation. The proposed method contributes to revealing the mechanism of combustion instability and improving the reliability of liquid rocket engines.

具有振荡的喷射器的流量特性在燃烧不稳定的机制中起着重要作用。燃烧不稳定会降低发动机的可靠性。因此，提出了一种基于 VOF-to-DPM 模型的有效方法来评估入口质量流量振荡对液体火箭发动机喷射器的影响。该方法采用VOF-to-DPM模型来模拟喷油器在振荡下的整个喷雾过程，该模型能够以比VOF方法更少的计算成本来描绘完整的喷雾过程。所提出的方法首先通过所报告的模拟工作进行验证。然后，应用该方法研究了单缸旋流喷射器在不同入口下的流动特性（响应和喷雾特性）质量流量振荡。该方法的结果表明，单纯旋流喷射器对 200-300 Hz 的振荡敏感，这与报道的实验工作一致。此外，入口振荡频率主要增加相位差，而频率和振幅共同决定出口质量流量的放大或衰减。与其他振荡频率相比，250 Hz 的喷射器具有更高的下游再循环速度和更小的液滴，这可能会引起燃烧不稳定。数值结果有利于喷油器设计并通过主动调节降低燃烧不稳定的可能性。该方法有助于揭示燃烧不稳定机理并提高液体火箭发动机的可靠性。