Experimental Analysis of different shaped ribs on heat transfer and fluid flow characteristics

Sandeep S Kore,Satish Chinchanikar,Pravin Hujare,Sunil V Dingare,Ashok Mache,S.B Sanap,Mathew V K Mathew V K,V.K Bhojwani

doi:10.1051/e3sconf/202017001019

Abstract

There are number of applications such as gas turbines, solar air heating, electronics cooling and heat exchangers, where internal cooling passage is observed. For heat transfer augmentation inside these cooling passages different techniques are used like dimpled surface, wings and ribs. Ribs are used in most of the devices for internal cooling. The ribs disturb the boundary layer and increase the turbulent kinetic energy which enhances the heat transfer rate. Most of the researchers concentrate on square and rectangular shaped ribs. The cross section of the rib plays important role in the production of flow field. The shape of ribs affects on boundary layer separation, attachment and hot spots created. In the present paper heat transfer and fluid flow characteristics from rib roughened rectangular duct with different shapes of ribs were investigated. The experimental set up consists of rectangular channel of aspect ratio 4. The pitch to width ratio was varied as 5, 7.5 and 10 respectively. The Reynolds number was varied as 6000 to 30000. The ribs used for the investigations were square, house and boot shaped. From the investigations it is observed that boot shaped rib is having higher thermal performance than other two geometries

Highlights

The output in terms of efficiency & power of any thermal device increases by increasing turbine inlet temperature
The present turbine blades are exposed to temperature near about 1800K, which is higher than their melting temperature
The experimental set up is validated with Dittus-Boelter correlation for heat transfer as shown in Fig.[4].The percentage deviation between theoretical and experimental value is below 6%

Summary

Introduction

The output in terms of efficiency & power of any thermal device increases by increasing turbine inlet temperature. The turbine blades and vanes are cooled by internal passage in which different turbulators are used to augment the heat transfer. Higher inlet temperatures are able to be reached and thereby improving thermal efficiency and performance. There are holes where the coolant, after entering the blade, is pushed out of these holes and creates this layer which acts as a barrier. This layer protects the blade and keeps it cooler than without the film. Researchers have investigated internal cooling passage using various heat transfer augmentation techniques likes dimpled surface, twisted tape, flow blockage and ribs[1,2]. In present experimental work house shape and boot shaped ribs are investigated experimentally

Methods

Results

Conclusion