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International Journal of Mechanical Engineering and Technology (IJMET)Volume 8, Issue 5, May 2017, pp.

Available online at http://www.iaeme.com/IJME

ISSN Print: 0976-6340 and ISSN Online: 0976

© IAEME Publication

STUDY OF HEAT TRANSF

RECTANGUL

K.Rakesh Sai, D.Gowru Naidu,

Department of Mechanical Engineering

ABSTRACT

Gas turbine plays an important role in present day industries. These turbines are

being widely used for the generation of power in large scale and also in the aircraft

propusion. The main challenge is to increase the performance and efficiency o

gas turbines and this can be done by raising the inlet temperature of the turbine. Now

a days gas turbine became more advanced and the inlet temperatures are as high as

17000c, where as the blade materials can withstand

compressor in the turbine extracts pressure in the form of a cooling air temperature

ranging 6500c. This cooling air is going to pass through the blade airfoil sections to

lower the temperature to 10000c which is safe for the operation of engine.

The gas turbine blade consists of cooling passages which are very complex, so it is

difficult for designers to accurately predict the metal temperature. The

aerothermodynamics in these airfoil sections are complex and there exists a large

thermal gradient through out the blade profile and hence the heat transfer coefficients

will be high. The heat transfer on the surfaces of the blade passages increases as the

flow enters into turbine and accelerates around the blade. For any type of complex

flows and high for high inlet temperatures designers need extensive experimental and

numerical data to help them in developing efficient cooling techniques. Detailed hot

gas path , heat transfer distribution , temperature distribution will help in developing

efficient airfoil section profiles.

Practically ,it is very complex to obtain the experimental data on the heat transfer

in thin airfoil sections of the turbine blade. The experiments were carried out on a

rectangular duct of aspect ratio 2:1. Air is used as a working flui

part is going to perform in ANSYS Workbench by using Fluent Flow analysis.

Key words: Reynolds Number, Nusselts Number,

Velocities, Heat Transfer Coefficient

Cite this Article: K.Rakesh Sai, D.Gowru Naidu, G.Balu Mahendra,

Y.V.Satyanarayana and CH.Siva Krishna

Rectangular Duct in A Gas Turbine

and Technology, 8(5), 2017

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IJMET/index.asp 490 editor@iaeme.com

International Journal of Mechanical Engineering and Technology (IJMET) 2017, pp. 490–495, Article ID: IJMET_08_05_052

http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=5

6340 and ISSN Online: 0976-6359

Scopus Indexed

TUDY OF HEAT TRANSFER THROUGH

RECTANGULAR DUCT IN A GAS TURBINE

Gowru Naidu, G.Balu Mahendra, Y.V.Satyanarayana,

Krishna

Mechanical Engineering, KL University, AP,

Gas turbine plays an important role in present day industries. These turbines are

being widely used for the generation of power in large scale and also in the aircraft

propusion. The main challenge is to increase the performance and efficiency o

gas turbines and this can be done by raising the inlet temperature of the turbine. Now

a days gas turbine became more advanced and the inlet temperatures are as high as

17000c, where as the blade materials can withstand a temperature up to 13500c. Th

compressor in the turbine extracts pressure in the form of a cooling air temperature

ling air is going to pass through the blade airfoil sections to

lower the temperature to 10000c which is safe for the operation of engine.

s turbine blade consists of cooling passages which are very complex, so it is

difficult for designers to accurately predict the metal temperature. The

aerothermodynamics in these airfoil sections are complex and there exists a large

h out the blade profile and hence the heat transfer coefficients

will be high. The heat transfer on the surfaces of the blade passages increases as the

flow enters into turbine and accelerates around the blade. For any type of complex

gh inlet temperatures designers need extensive experimental and

numerical data to help them in developing efficient cooling techniques. Detailed hot

gas path , heat transfer distribution , temperature distribution will help in developing

section profiles.

Practically ,it is very complex to obtain the experimental data on the heat transfer

in thin airfoil sections of the turbine blade. The experiments were carried out on a

rectangular duct of aspect ratio 2:1. Air is used as a working fluid. All the analysis

part is going to perform in ANSYS Workbench by using Fluent Flow analysis.

Reynolds Number, Nusselts Number, Average Temperatures, Inlet

Heat Transfer Coefficient.

K.Rakesh Sai, D.Gowru Naidu, G.Balu Mahendra,

Y.V.Satyanarayana and CH.Siva Krishna Study of Heat Transfer Through

Rectangular Duct in A Gas Turbine. International Journal of Mechanical Engineering

), 2017, pp. 490–495.

com/IJMET/issues.asp?JType=IJMET&VType=8&IType=5

editor@iaeme.com

T&VType=8&IType=5

ER THROUGH

GAS TURBINE

Y.V.Satyanarayana, CH.Siva

India.

Gas turbine plays an important role in present day industries. These turbines are

being widely used for the generation of power in large scale and also in the aircraft

propusion. The main challenge is to increase the performance and efficiency of the

gas turbines and this can be done by raising the inlet temperature of the turbine. Now

a days gas turbine became more advanced and the inlet temperatures are as high as

a temperature up to 13500c. The

compressor in the turbine extracts pressure in the form of a cooling air temperature

ling air is going to pass through the blade airfoil sections to

lower the temperature to 10000c which is safe for the operation of engine.

s turbine blade consists of cooling passages which are very complex, so it is

difficult for designers to accurately predict the metal temperature. The

aerothermodynamics in these airfoil sections are complex and there exists a large

h out the blade profile and hence the heat transfer coefficients

will be high. The heat transfer on the surfaces of the blade passages increases as the

flow enters into turbine and accelerates around the blade. For any type of complex

gh inlet temperatures designers need extensive experimental and

numerical data to help them in developing efficient cooling techniques. Detailed hot

gas path , heat transfer distribution , temperature distribution will help in developing

Practically ,it is very complex to obtain the experimental data on the heat transfer

in thin airfoil sections of the turbine blade. The experiments were carried out on a

d. All the analysis

part is going to perform in ANSYS Workbench by using Fluent Flow analysis.

Average Temperatures, Inlet

Study of Heat Transfer Through

al of Mechanical Engineering

com/IJMET/issues.asp?JType=IJMET&VType=8&IType=5

K.Rakesh Sai, D.Gowru Naidu, G.Balu Mahendra, Y.V.Satyanarayana and CH.Siva Krishna

http://www.iaeme.com/IJMET/index.asp 491 editor@iaeme.com

1. INTRODUCTION

The purpose of gas turbine technology is to extract the maximum energy from the high

temperature high pressure gases produced by combustor. This could be achieved by

improving the thermal efficiency of the gas turbine engine. Attempts were being made to

increase the power output and thermal efficiency of a gas turbine engine by operating turbine

at elevated temperatures as it is understood that the efficiency of gas turbine is a direct

function of turbine inlet temperature.

Turbine blades are the individual components which make up the turbine section of a gas

turbine engine and are responsible for extracting energy from the high temperature, high

pressure gases produced by the combustor. The turbine blades are often the limiting

component and were considered as the critical components of the gas turbine engines in

which failures occur frequently.

Gas turbines play a vital role in the today’s industrialized society, and as the demands for

power increase, the power output and thermal efficiency of gas turbines must also increase.

Modern high-speed aero-engines operate at elevated temperatures about 2000 K to achieve

better cycle efficiencies. However, the presently available alloys cannot resist temperatures

much higher than 1350 K. Internal cooling techniques for gas turbine blades have been

studied for several decades. The internal cooling techniques of the gas turbine blade includes:

jet impingement, rib tabulated cooling, and pin-fin cooling which have been developed to

maintain the metal temperature of turbine vane and blades within acceptable limits in this

harsh environment.

2. MODELLING & DESIGNING OF DUCT

Modelling and designing are the key elements for any analysis and experimental procedure.

This process can be done by using any of the modelling software .

Even in analysis software also it is possible to model a simple geometry. In ANSYS

workbench we can draw our geometry. Cross section of the rectangular duct is 50 × 25 mm

length of the duct is 500mm.

Study of Heat Transfer Through Rectangular Duct in A Gas Turbine

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3. EXPERIMENTAL RESULTS

Temperature varying with position ‘m’

Reynolds number 5000

Reynolds number 10000

Study of Heat Transfer Through Rectangular Duct in A Gas Turbine

IJMET/index.asp 492 editor@iaeme.com

EXPERIMENTAL RESULTS

emperature varying with position ‘m’

Study of Heat Transfer Through Rectangular Duct in A Gas Turbine

editor@iaeme.com

K.Rakesh Sai, D.Gowru Naidu, G.Balu Mahendra, Y.V.Satyanarayana and CH.Siva Krishna

http://www.iaeme.com/IJMET/index.

Reynolds number 15000

Reynolds number 20000

K.Rakesh Sai, D.Gowru Naidu, G.Balu Mahendra, Y.V.Satyanarayana and CH.Siva Krishna

IJMET/index.asp 493 editor@iaeme.com

Reynolds number 20000

K.Rakesh Sai, D.Gowru Naidu, G.Balu Mahendra, Y.V.Satyanarayana and CH.Siva Krishna

editor@iaeme.com

Study of Heat Transfer Through Rectangular Duct in A Gas Turbine

http://www.iaeme.com/IJMET/index.asp 494 editor@iaeme.com

Table showing the results for our analysis

Reynolds number 5000 10000 15000 20000

Velocity inlet (m/s) 2.89 4.28 6.2 10.6

Temperature (K) 390 354.5 343 326

Heat transfer

coefficient (W/(m2•K)

10.16 15.05 20.12 24.65

Nusselts number 5.9 8.88 12.13 16.14

4. CONCLUSIONS

From this analysis we can conclude that as we increase the Reynolds number both the inlet

velocities and heat transfer coefficient increases , where as the temperatures decreased. The

heat transfer on the surfaces of the blade passages increases as the flow enters into turbine and

accelerates around the blade. For any type of complex flows of a turbines and for high inlet

temperatures, designers need extensive experimental and numerical data to help them in

developing efficient cooling techniques.

5. FUTURE SCOPE

Based on our present analysis in future we are going to work on getting some more extensive

experimental data such as detailed hot gas path heat transfer distribution , temperature

distribution. This will help in developing efficient airfoil section profiles and also we can

increase the efficiency of the gas turbine.

REFERENCES

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[3] Çengel, Y. A. and Turner, R. H. (2001). Fundamentals of Thermal-Fluid Sciences,

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K.Rakesh Sai, D.Gowru Naidu, G.Balu Mahendra, Y.V.Satyanarayana and CH.Siva Krishna

http://www.iaeme.com/IJMET/index.asp 495 editor@iaeme.com

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