Preparing Methane – Air Mixture Using Ejector

In this research, a two – dimensional numerical investigation is conducted to show the ability of the jet-ejector to prepare the air – methane mixture at different equivalence ratio. The basic dimensions (diameters ratio, throat length, angle α, and angle θ) of the jet-ejector are taken into account on calculating the equivalence ratio. The results showed that the ratio of the diameters has a higher effect than other parameters on preparing a mixture for equivalent ratios including both rich and lean mixture. The rest of the factors did not have a significant effect on the value of the equivalence ratio, and only had a role in preparing an equivalence ratio for rich mixture type.

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Effects of dwell time of split injection on mixture formation and combustion processes of diesel spray

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/09544070211053693 ◽

2021 ◽

pp. 095440702110536

Author(s):

Samir Chandra Ray ◽

Jaeheun Kim ◽

Scinichi Kakami ◽

Keiya Nishida ◽

Youichi Ogata

Keyword(s):

Dwell Time ◽

Equivalence Ratio ◽

Diesel Spray ◽

Spray Combustion ◽

Mixture Formation ◽

Split Injection ◽

Lean Mixture ◽

Rich Mixture ◽

The Rich ◽

Combustion Processes

The effects of dwell time on the mixture formation and combustion processes of diesel spray are investigated experimentally. A commercial multihole injector with a 0.123 mm hole diameter is used to inject the fuel. The injection procedure is either a single or split injection with different dwell times, whereas the total amount of injected fuel mass is 5.0 mg per hole. Three dwell times are selected, that is, 0.12, 0.32 and 0.54 ms, with a split ratio of 7:3 based on previous findings. The vapour phase is observed, and the mixture formation pertaining to the equivalence ratio is analysed using the tracer laser absorption scattering (LAS) technique. A high-speed video camera is used to visualise the spray combustion flame luminosity, whereas a two-colour pyrometer system is used to evaluate the soot concentrations and flame temperature. An analysis of the mixture formation based on the spray evaporating condition reveals a more concentrated area of the rich mixture within a 0.32 ms dwell time. In the shortest dwell time of 0.12 ms, the equivalence ratio distribution decreases uniformly from the rich mixture region to the lean mixture region. In the case involving a shorter dwell time, a suitable position for the second injection around the boundaries of the first injection is obtained by smoothly growing the lean mixture and avoiding the large zone of the rich mixture. Therefore, the shortest dwell time is acceptable for mixture formation, considering the overall distribution of the equivalence ratios. Spray combustion analysis results show that the soot formation rate of the single injection and 0.32 ms dwell time case is high and decreases quickly, implying a rapid reduction in the high amount of soot. Consequently, 0.12 ms can be considered the optimal dwell time due to the ignition delay and relatively low soot emission afforded.

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