International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Impact Factor (2012): 3.358 Volume 3 Issue 7, July 2014 www.ijsr.net Licensed Under Creative Commons Attribution CC BY Comparative Analysis of Gas Turbine Blades with and without Turbulators Sagar H T 1 , Kishan Naik 2 1 PG Student, Dept. of Studies in Mechanical Engineering, University BDT College of Engineering, Davangere, India 2 Assistant Professor, Dept. of Studies in Mechanical Engineering, University BDT College of Engineering, Davangere, India Abstract: In typical gas turbine engines nozzle guide vanes are (NGV) endure the highest operating temperatures. There exists a great drive in the turbine industry to increase the turbine entry temperature leading to higher thermal efficiency. The present gas turbine engines requires higher entry turbine entry temperatures as engines are operating at higher thrust and thermal efficiency at the same time by operating a turbine at higher temperature reduces the life of blades or vanes because of thermal stresses. Sometimes, the turbine entry temperatures may nearly equal to melting point turbine blade material. Therefore, it is required to cool the blades or vanes to a temperature which gives more life to blades or vanes. The present work aims to determine a better internal cooling configuration which gives optimal temperature distribution on blade surface. Conjugate heat transfer analysis has been carried out to find out the performance and thermal distribution on the existing blade with and without internal cooling on nozzle guide vane by using CFD code ANSYS CFX. In this work, CFD analysis has been carried out using Reynolds average Navier stokes equations. Comparative analysis was done with and without cooling channel on the Nozzle Guide Vane and average temperature on the nozzle guide vane surface will be estimated. Four cooling channels with Turbulators provided better cooling compared to all configurations, because the presence of turbulators provides additional turbulence and increases heat transfer surface area. Higher turbulence provides better heat transfer. Keywords: Gas turbine, Cooling channel, Computational fluid dynamics, Heat transfer. 1. Introduction A turbine is a rotary mechanical device that extracts energy from a combustion chamber and converts it into useful work. A turbine is a turbo machine with at least one moving part called a rotor assembly, which is a shaft or drum with blades attached. Turbine blades move and impart rotational energy to the rotor. Generally Turbine blades are of two types namely, Rotor and Stator. Rotors are rotational blades and the stators are stationary vanes. Since the turbine gets energy from the combustion chamber, the turbine is exposed to high temperature. For this purpose various types of high temperature materials and alloys are used to withstand the high temperature exposed from the combustion chamber. Generally if the outlet temperature of the engine get increased then the efficiency and the performance of the engine get increased, but increasing the temperature causes the turbine material to get damage and leads to engine malfunction. To overcome this malfunction various high temperature withstanding material and alloy are used. But, presently we employed various heat transfer cooling technique which makes the material to withstand more temperature than its critical temperature and makes the increase in efficiency of the engine. [3] Dr. D. A. Rowbury et al [1] numerically investigated cooling research that aims to develop and validate design methods to give maximum cooling effectiveness for minimum cooling flow. The prime objective of this project is to deliver an integrated research package for the development and validation of numerical methods for the design and off design analysis of turbine blade cooling systems. Jenny Sundberg et al [2] numerically investigated the relationship between inlet temperature, specific power and efficiency, have led to great engineering efforts in the attempt to push the temperature to higher and higher levels. Hasan Nasir et al [3] numerically investigated the turbine blade tip leakage flow from blade pressure side to suction side over the tip surface increases the thermal loading to the blade tip, leading to a high local temperature and thus, is considered one of the primary sources of blade failure. Leakage flow can be reduced by using a Recessed or squealer tip blade or by cooling the blade tip to incorporate film cooling. Experiments were performed for plane tip and squealer tip for different coolant to mainstream blowing ratios of 1.0, 2.0, and 3.0.A transient infrared (IR) thermography technique was used to simultaneously measures heat transfer coefficient and film cooling effectiveness. The Reynolds number based on cascade exit velocity and axial chord length and the inlet and exit Mach numbers were 0.16 and 0.55, respectively. Results showed that performance of the full pressure side squealer was the poorest and that a squealer tip performs better than the plane tip blade. Thermal efficiency of a gas turbine engine can be improved by increasing the turbine inlet gas temperature. As turbine inlet temperature is increased, there is a greater need for more efficient cooling. A turbine blade operates typically at temperature 1650-1750° K, pressure 1.20-1.70 Mpa and in addition to that it rotates at the speeds greater than 3000 rpm. So, efficient cooling mechanisms are needed to improve blade life and overall efficiency of the turbine. Thus heat transfer augmentation inside airfoil internal channels is an important issue for the gas turbine industry. Present material cannot withstand such high thermal stresses in this extreme operating environment of pressure and temperature. Therefore, standard metallic blades with sophisticated cooling techniques have been employed for turbine blades in order to maintain safe and long operation of the turbines under extreme operating conditions [4]. Paper ID: 0201412901 1407