(1-24) Effect of Recessed-Wall on an Impingement Diesel Spray((FS-2)Fuel Sprays 2-Diesel sprays)

Abstract

Behavior of spray impinged on a recessed-wall was experimentally investigated as a new concept of impingement diesel spray. The spray injected through a diesel nozzle impinged vertically on the center of the circular recess. Spray height as well as spray path penetration was measured at various timings on high speed photographs of the spray, which was injected by a single shot injection system into a high pressure chamber. The spray after impinging on the recessed-wall was reflected from the recess with rolling up motion more than the impingement spray on a flat wall (upper photographs in Fig. 1). However, in a case that the spray width at the wall location was wider than the recess diameter, the spray after impingement expanded along the wall (lower photographs in Fig. 1). Figure 2 shows parameters of spray impinging on a recessed-wall. The spray behavior on the recessed wall was controlled more by the width-to-diameter ratio Ws/Dr than by the recess diameter (Fig. 3). Also, for the purpose of increasing the spray height, it is necessary that the value of Ws/Dr should be around 0.5 (Fig. 4). At this ratio, the rolling-up motion was observed clearly and strongly on the recessed-wall.