Numerical simulations coupled with LDV experiments were carried out to investigate a slot jet issued into a cross flow, which is relevant in the film cooling of gas turbine combustors. The film cooling fluid injection from slots or holes into a cross-flow produces highly complicated flow fields. In this paper, the time-averaged Navier-Stokes equations were solved on a collocated body-fitted grid system with the V2F turbulence model. The fluid flow and turbulent Reynolds stress fields were compared with the LDV experiments for three jet angles, namely, 30-deg, 60-deg, and 90-deg, and the jet blowing ratio is ranging from 2 to 9. Good agreement was obtained. Therefore, the present solution procedure was also adopted to calculations of 15-deg and 40-deg jets. In addition, the temperature fields, which were difficult to measure by experimental methods, were also computed with a simple eddy diffusivity model to obtain the film cooling effectiveness which was used for evaluation of the various jet-cross-flow arrangements. The results show that a recirculation bubble downstream the jet exists for jet angles larger than 40-deg, but it vanishes when the angle is less than 30-deg, which is in good accordance with the experiments. The blowing ratio has a large effect on the size of the recirculation bubble, and consequently on the film cooling effectiveness. In addition, the influence of boundary conditions for the jet and cross-flow are also addressed in the paper.
|Conference||ASME Summer Heat Transfer Conference (HT2003), 2003 |
|City||Las Vegas, NV|
|Period||2003/07/21 → 2003/07/23|
- Slot film cooling
- Recirculation bubbles