Performance evaluation of a transpiration-cooled gas turbine for different coolants and permissible blade temperatures considering the effect of radiation

Author(s):  
S Kumar ◽  
O Singh

Successful gas turbine technology is based significantly upon the introduction of new blade materials with increased permissible temperature for gas turbine blades and/or the use of efficient means and methods of turbine blade cooling in order to achieve the highest possible turbine inlet temperature. The gas turbine blade cooling models found in literature indicate that the effect of radiation from elevated temperature gases is generally not considered. However, the radiative heat transfer always occurs owing to the presence of mainly carbon dioxide and water vapour in the combustion products. The present paper deals with the comparative study of transpiration-cooled gas turbine cycle performance with and without taking radiation effect for different coolants and permissible blade temperature. The thermodynamic evaluation shows that, with consideration of the radiation effect, the theoretical coolant requirement increases so as to be close to the actual requirement and hence the cycle performance is affected accordingly. The transpiration-cooled gas turbine cycle performance parameter variations are presented to exemplify the role of cooling technology, cooling means, and material development, taking the radiation effect into account.

2012 ◽  
Vol 505 ◽  
pp. 539-543
Author(s):  
Kyoung Hoon Kim ◽  
Kyoung Jin Kim ◽  
Chul Ho Han

Since the gas turbine systems require active cooling to maintain high operating temperature while avoiding a reduction in the system operating life, turbine blade cooling is very important and essential but it may cause the performance losses in gas turbine. This paper deals with the comparative thermodynamic analysis of gas turbine system with and without regeneration by using the recently developed blade-cooling model when the turbine blades are cooled by the method of film cooling. Special attention is paid to investigating the effects of system parameters such as pressure ratio and turbine inlet temperature on the thermodynamic performance of the systems. In both systems the thermal efficiency increases with turbine inlet temperature, but its effect is less sensitive in simpler system


2021 ◽  
Vol 39 (2) ◽  
pp. 403-416
Author(s):  
Chirag Sharma ◽  
Siddhant Kumar ◽  
Aanya Singh ◽  
Kartik R. Bhat Hire ◽  
Vedant Karnatak ◽  
...  

Developments in the gas turbine technology have caused widespread usage of the Turbomachines for power generation. With increase in the power demand and a drop in the availability of fuel, usage of turbines with higher efficiencies has become imperative. This is only possible with an increase in the turbine inlet temperature (TIT) of the gas. However, the higher limit of TIT is governed by the metallurgical boundary conditions set by the material used to manufacture the turbine blades. Hence, turbine blade cooling helps in drastically controlling the blade temperature of the turbine and allows a higher turbine inlet temperature. The blade could be cooled from the leading edge, from the entire surface of the blade or from the trailing edge. The various methods of blade cooling from leading edge and its comparative study were reviewed and summarized along with their advantages and disadvantages.


2012 ◽  
Vol 224 ◽  
pp. 256-259
Author(s):  
Kyoung Hoon Kim ◽  
Kyoung Jin Kim ◽  
Hyung Jong Ko

When water is injected at an inlet of compressor, wet compression occurs due to evaporation of water droplets. In this work, the effects of wet compression on the performance of regenerative gas turbine cycle with turbine blade cooling are analytically investigated. For various pressure ratios and water injection ratios, the important system variables such as ratio of coolant flow for turbine blade cooling, fuel consumption, specific power and thermal efficiency are estimated. Parametric studies show that wet compression leads to significant enhancement in both specific power and thermal efficiency in gas turbine systems with turbine blade cooling.


Author(s):  
Aaron R. Byerley ◽  
August J. Rolling

Since the 1950’s, the turbine inlet temperatures of gas turbine engines have been steadily increasing as engine designers have sought to increase engine thrust-to-weight and reduce fuel consumption. In turbojets and low-bypass turbofan engines, increasing the turbine inlet temperature boosts specific thrust, which in some cases can support supersonic flight without the use of an afterburner. In high-bypass gas turbine engines, increasing the turbine inlet temperature makes possible higher bypass ratios and overall pressure ratios, both of which reduce specific fuel consumption. Increased turbine inlet temperatures, without sacrificing blade life, have been made possible through advances in blade cooling effectiveness and high-temperature turbine blade materials. Investigating the impact of higher turbine inlet temperatures and the corresponding cooling air flow rates on specific thrust, specific fuel consumption, and engine development cost is the subject of this paper. A physics-based cooling effectiveness correlation is presented for linking turbine inlet temperature to cooling flow fraction. Two cases are considered: 1) a low-bypass, mixed-exhaust, non-afterburning turbofan engine intended to support supercruising at Mach 1.5 and 2) a high-bypass, unmixed-exhaust turbofan engine intended to support highly efficient, long range flight at Mach 0.8. For each of these two cases, both baseline and enhanced cooling effectiveness values as well as both baseline and elevated turbine blade material temperatures are considered. Comparing these cases will ensure that students taking courses in preliminary engine design understand why huge research investments continue to be made in turbine blade cooling and advanced, high-temperature turbine blade material development.


At present, Gas turbines play an essential responsibility in different areas such as jet, generating power and various commercial and industrial sectors. Melting point of the turbine blade may causes the hotness levels which go rapidly raise. Likewise, heavy crack may cause because of Turbine Inlet Temperature (TIT) at turbine blades for the period of expansion procedure of turbine sector. Hence, a highly developed blade cooling system is required for safe operation of turbines. The proposed system deals with the serpentine rip - roughened passage with micro pin fin cooling system and it has been analyzed corresponding to serpentine cooling system. It increases the heat transfer enhancement. Therefore, very warm gases in and around the turbine blade may have a stream temperature at 1500K. On the other side, cool air disclosed to the blade core duct and an entry temperature may have been 650K. The proposed systems with 2D and 3D model were developed by using CATIA. The 3D design is then analyzed using CFD. Further, the corresponding results of serpentine rip - roughened passage and micro pin fin arrangement in serpentine rip-roughened passage are compared and the details are presented.


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