Computational Study of Air/Mist Impinging Jets Cooling Effectiveness under Various Curvature Models

Efficiency is one of the most important parameters in evaluating the performance of a gas turbine engine by increasing the turbine inlet temperature, which could increase the gas turbine cycle's efficiency. In order to increase the turbine inlet temperature significantly, an advanced cooling system needs to be researched and developed. This paper will establish a double chamber model simulating mist impingement cooling under typical gas turbine operating conditions of high temperature and pressure. Numerical simulations are examined to investigate the curvature and mist effect of air impingement cooling. The air impingement cooling can be significantly affected by the curvature which is measured by central angle. The 30 degrees central angle model has a better cooling effectiveness than the flat surface model, while the 90 degrees central angle model has the lowest cooling performance. Under real gas turbine operating conditions at high temperature, pressure, and velocity, comparing with the 90 degrees central anglemodel, the 30 degrees central angle model air impingement cooling's enhancement could be better than 98% and provides a wall cooling of approximately 175K. By adding mist, impingement cooling effectiveness can be enhanced approximately by 64% on the 90 degrees central angle model and by 6-10% on the other models.