低出力レーザ後方散乱LDVによるシリンダ内流速測定の可能性

抄録

Many pepers have been published on the measurements of in-cylinder flow of an engine, because flow velocity affects to heat transfer to the cylinder walls, and the turbulence intensity also affects the combustibility of the fuel air mixture. Backward scattered LDV is considered to be suitable for measuring the in-cylinder flow on account of its flexibility in application to the engine. However, the demerit of this method is the weak scattered light from the scattering particles. Hence a high powered laser and normal optics are needed and the system is to be so complexed. One of the revisions for the backward scatterd LDV is to use optical fiber to simplify the optics, but this method has demerits of slight scattered light and poor spatial resolution. If it is possible to measure using backward scattered LDV of a low power laser, the measuring system can be more simplified and useful. Therefore, in this paper, the capability of using a low power laser for LDV is studied with revised optics, a signal processor, and scattering particles, and finally the system is applied to an engine and reasonable velocity was measured. Thus the capability of backward scattered LDV using a low power laser is confirmed.