Open Access

ARTICLE

Diffusion of a Nonvolatile Fuel Spray in Swirl Flow

by Yanju Wei^1,*, Jie Zhang¹, Shengcai Deng¹, Yajie Zhang¹, Yajing Yang², Hao Chen³

1 School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, 710049, China
2 State Key Laboratory of Mechanical Strength and Vibration, School of Aerospace, Xi’an Jiaotong University, Xi’an, 710049, China
3 School of Automobile, Chang’an University, Xi’an, 710061, China

* Corresponding Author: Yanju Wei. Email:

(This article belongs to the Special Issue: Sustainable energy for transport)

Energy Engineering 2021, 118(1), 73-87. https://doi.org/10.32604/EE.2020.012482

Received 01 July 2020; Accepted 17 August 2020; Issue published 17 November 2020

Abstract

The diffusion of fuel spray in swirl flow is vital for the combustion of diesel engine, however, the researches on this is still mysterious due to the obstacles on direct investigations on a real engine. The research of intake swirl in engine at present normally use CFD simulation or based on data analysis of combustion and exhaust emission, the specific mixing process of fuel in swirl flow still not very clear. In this paper, a rapid compression machine (RCM) with an optical combustion chamber was established with the mean compression velocity of 7.55 m/s. Three kinds of flow fields, including intense swirl field, weak swirl field and turbulent field, were conducted to investigate the diffusion characteristics of injected fuel, the mixing processes of fuel spray in the swirl flow fields were recorded by the high-speed camera. Experimental results show that the mixing of fuel spray in air consists of four stages: fuel injection, wall approaching, rapid diffusion and final diffusion. The fuel spray is firstly bended by the lateral flow of the swirl field, then liquid fuel is blown onto, and coats on, the sidewall. The fuel on the sidewall is finally enrolled into the chamber plenum afterwards in gaseous phase via the spiral arms (in swirl fields) or random routes (in turbulent field) At last the fuel disperses all over the chamber. The results give an intuitive observation and help better understand the air-fuel mixing process in diesel and direct inject gasoline engines.

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Keywords

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