Effect of Local Momentum Ratio on Spray Windward Distribution of a Gas–Liquid Pintle Injector Element

The variable-area pintle injector has unique geometry and spray characteristics compared to traditional coaxial injectors, is advantageous for weight lightening deep throttling of liquid rocket engines. To obtain an accurate prediction the windward distribution a gas–liquid with discrete radial orifices, element using air water as simulants was designed experiments in atmospheric environment. air-film injection pressure drop water-jet orifice diameter were both adjusted wide variance range from 0.19 2.85 local momentum ratio. Backlight imaging adopted shooting frozen pattern one side, new dimensionless parameter, i.e., fraction, defined quantitatively analyze time-averaged boundary band. band model circular-orifice jet corresponding derivative formula half angle summarized through parameter study. predicted results empirical models good agreement experimental results. It found that when ratio about 1, basically overlapped coverage scope gas film uniform mist.