Search Results

An advanced laser 2-focus velocimeter (L2F) has been applied to the measurement of droplet velocities and sizes in a dense region of diesel fuel spray. The maximum rate of data sampling of the L2F was set at 15 MHz. The fuel was injected into the atmosphere by using a common rail injector. The rail pressure was set at 40 and 70 MPa. The nozzle hole diameter of the injector was 0.113 mm. The L2F can detect droplets just after the spray tip reaches the measurement position 30 mm downstream from the nozzle. The result of the measurement shows that the higher injection pressure leads the higher droplet velocity in the core of the spray. It is clearly shown that the smaller droplets after active disintegration are dispersed spatially under higher injection pressure.

A laser 2-focus velocimeter (L2F) has been applied for the measurements of velocity and size of droplets in the core region of diesel spray. The L2F had a micro-scale probe which consists of two foci. The distance between two foci was 14 μm and the focus size was nominally 3 μm. Valid data were extracted by the criteria that a downstream signal was sequentially observed after an upstream signal. The maximum data sampling rate of the L2F was set at 15 MHz. Fuel was intermittently injected into the atmosphere by using a common rail injector. The nozzle orifice diameter of the injector was 0.113 mm and the injection pressure was set at 70 MPa. Five measurement positions were located in the plane of 15 mm from the nozzle orifice. The L2F could detect droplets just after the spray tip reached the measurement position. Measurement result showed that the velocity and size of droplets in the spray core decreased at the off-axis region.

A laser 2–focus velocimeter (L2F) has been applied for the measurements of velocity and size of droplets in the core region of diesel spray. The L2F had a micro–scale probe which consists of two foci. The distance between two foci was 14 µm and the focus size was nominally 3 µm. Valid data were extracted by the criteria that a downstream signal was sequentially observed after an upstream signal. The maximum data sampling rate of the L2F was set at 15 MHz. Fuel was intermittently injected into the atmosphere by using a common rail injector. The nozzle orifice diameter of the injector was 0.113 mm and the injection pressure was set at 70 MPa. Five measurement positions were located in the plane of 15 mm from the nozzle orifice. The L2F could detect droplets just after the spray tip reached the measurement position. Measurement result showed that the velocity and size of droplets in the spray core decreased at the off–axis region.