An experimental investigation of the flow characteristics in the swirl chamber of a C.I. Engine

The global flow characteristics such as mean velocity, turbulence intensity and scales of turbulence have been measured in a swirl combustion chamber of a Compression Ignition engine using a constant temperature hot-wire anemometer. The experiments were conducted at 400 rpm under motoring (non-firing) conditions. Ensemble averaging procedure was adopted to calculate the mean velocity and turbulence intensity after comparing the merits and demerits of this method with the Individual Cycle Mean method and the Frequency Separation method. The experimental results indicate that the mean velocity and turbulence intensity show significant spatial and temporal variations in the swirl chamber. These variations are observed to be maximum from 60 deg. bTDC to TDC of compression. The values of mean velocity at chamber periphery are found to be higher than the values near the chamber axis. Macro-time scale varies from about 160 to 530 μs and macro-length scale varies from about 2.5 to 5.5 mm during the last part of the compression stroke at 400 rpm and at the compression ratio of 8.5. The effect of speed and compression ratio on flow velocity has also been studied. © Copyright 1991 Society of Automotive Engineers, Inc.