CFD Analysis of RIB Turbulated Cooling in Gas Turbine Blades

Abstract

Gas Turbines are designed to continuously and efficiently generate useful power from fuel energy and are developed into very reliable high performance engines. Nowadays gas turbines have been put to use in various fields like, power plants, marine industries as well as for industrial propulsion. For high thermal efficiency advanced gas turbines use high temperature at the entry of the turbine. Therefore, for the purpose of increasing thermal efficiency of the turbines, it is imperative to design effective cooling schemes. The current Turbine Inlet Temperature in advanced gas turbines is much higher than the melting point of the blade material. As a result a varied range of cooling techniques are used to cool the blade to maintain normal operation of the turbine. An attempt has been made to computationally analyse the effects of one type of cooling system, rib turbulated cooling, wherein the cooling effects of air flow through a ribbed turbine blade passage has been simulated using ANSYSFLUENT. The mass flow rates of air through the passage was varied to observe the variation of cooling effects with mass flow rate and results were compared. The temperature contours of the blade for different mass flow rates were observed. The trends of different parameters like heat transfer coefficient, Nusselt number, skin friction coefficient was also noted. It was noted that although the cooling effects increase with increasing mass flow rate, the pressure loss due to friction also increases and hence it is not feasible to have high mass flow rates for cooling turbine blades.