Influences of Swirl and Turbulence on the Burning Velocity in an Engine Cylinder : 2nd Report, Experiment with Single-compression Test Equipment

Abstract

This paper deals with the influences of swirl and turbulence of a gas on the burning velocity in a cylinder using a single-compression test equipment, in which the flow conditions can be varied by changing the flow-in direction of the scavenging gas with adjustable vanes. The influences of the spark location and the rotational speed of the equipment on the burning velocity were also studied by means of both pressure measurements and direct photography of the flame propagation. The gas motion during the compression stroke was measured with a hot-wire anemometer and the result of analysis showed that in the case of a turbulent flow without swirl, the process of a change in kinetic energy of the gas could be expressed as follows. (e/ν3)1/4L =1.91(u^-L/ν)0.700 where e denotes the rate of a change in kinetic energy, ν the kinematic viscosity, u^- the mean velocity of response by a hot-wire, and L the height of the combustion chamber. The process of a change in kinetic energy was also discussed in the case of a turbulent flow with swirl.