Experimental investigation of high‐pressure hydrogen gas jet impingement characteristics of single‐hole cylindrical injector

Abstract

High‐pressure hydrogen direct injection technology can enable an internal combustion engine to attain high thermal efficiency and discharge clean emissions; hence, the advantages provided by hydrogen jet impingement are crucial. This paper presents an experimental investigation of the high‐pressure hydrogen direct injection from a single‐hole cylindrical injector. A test rig with a spring set was designed based on the impulse conservation law to test important high‐pressure hydrogen jet impingement parameters, such as jet impingement force and impulse. The results show that the hydrogen gas jet exhibits a two‐zone behavior. In Zone I (near‐field dynamic region), the jet impulse is not conservative, and the jet characteristic parameters (jet impingement force and impulse) fluctuate—first decreasing and then increasing. In Zone II, the jet impulse is conservative. This two‐zone jet feature is induced by shockwaves because a high‐pressure hydrogen jet with a high nozzle pressure ratio reaches its sonic speed at the nozzle outlet. The Mach disk height is the inflection point of these two zones. Moreover, the hydrogen injection pressure has a considerable influence on the gas jet. As the injection pressure increases, the hydrogen jet impingement force and impulse increase. Both jet parameters have a linearly increasing relationship with injection pressure.

Study on Combustion Characteristics of Low Concentration Coalbed Methane Induced by Hydrogen Jet based on Excess Air Ratio

“…Hydrogen jet can effectively improve the combustion speed of coalbed methane, and the selection of jet structure, jet pressure and environmental pressure is also crucial to the efficiency of the engine. With the increase of jet pressure, jet penetration distance will increase, and with the increase of environmental pressure, jet penetration distance will decrease [7][8][9]. Excess air coefficient is of great significance to the determination of antiknock and compression ratio of engine.…”