0445120059 0445120231 Common Rail Fuel Injector Compatible for Cummins SAA6d107e-1 Komatsu PC200-8

Dynamic cavitation inside a high performance diesel injector – an experimental and CFD investigation （part 4）

The 1000Bar equivalent case was simulated using the same scale pressure drop as calculated for the Large Scale Model. For the cavitation, a mixture model was used. This assumes that both liquid and vapour travel in a homogeneous multiphase flow; although not without limitations, it is a valid assumption for cavitating flows. Two incompressible phases are modelled, which is reasonable at the low pressure drops used in the large scale modelling.

The simulation of the 1000Bar equivalent injection pressure gave transient behaviour which matched the experimental results, as shown in Figure 3 with the eight experimental images from Figure 2. The frequency is 156Hz, giving excellent correlation with the experimental value of 160Hz. Movies of both the experimental flow and the CFD results show a striking similarity. The average value of Cd from the hybrid LESRANS model is 0.71. This gives excellent agreement with the value measured on the Large Scale Model. These results give confidence in the modelling and strong validation for the combination of turbulence and multiphase CFD models. Full details are given in [8].

Real-size CFD Modelling

The CFD model was run for the real size case and produced similar pulsation close to 150 kHz. The expected frequency from the scaling calculations is 160 kHz, which further confirms the method. 5. Discussion A realistic method has been demonstrated which enables the use of LES CFD modelling in product improvement. Some validation of the method has also been demonstrated, which is not common for LES CFD in this field.