Review of Forced Convection Heat Transfer Through a Non Circular Duct Provided with Different Types of Inserts

Among most of the conventional methods used to enhance the efficiency of a gas turbine, the one method which is commonly used is to increase the temperature at the inlet; thereby improving the power output and the efficiency. The internal cooling passages of blades are artificially roughened to improve the heat transfer performance. Modern gas turbines employ the application of inserts to enhance heat transfer through ducts. The reason behind the use of inserts is that they improves the turbulence in the fluid flow near the surface of the duct and creates obstruction to the laminar boundary layer to improve the heat transfer rate. The other reason is that the inserts also enhance the heat transfer rate by increasing the heat transfer area. The thermo hydraulic performance of the ribs is governed by many parameters such as the shape, size, angle and spacing. The present paper focuses on review of research work already done related to forced convection heat transfer through non circular ducts provided with different kind of inserts.