3-D Internal Flow and Conjugate Calculations of a Convective Cooled Turbine Blade With Serpentine-Shaped and Ribbed Channels

1999 ◽  
Author(s):  
Dieter E. Bohn ◽  
Volker J. Becker ◽  
Karsten A. Kusterer ◽  
Yokiu Otsuki ◽  
Takao Sugimoto ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Turbine Blade ◽  
Solid Body ◽  
Gas Turbines ◽  
Heat Transfer Analysis ◽  
Numerical Code ◽  
Cooling Channel ◽  
Flow And Heat Transfer ◽  
Body Regions

Modern cooling configurations for turbine blades include complex serpentine-shaped cooling channel geometries for internal-forced convective cooling. The channels are ribbed in order to enhance the convective beat transfer. The design of such cooling configurations is within the power of modem CFD-codes with combined heat transfer analysis in solid body regions. One approach is the conjugate fluid flow and heat transfer solver, CHT-Flow, developed at the Institute of Steam and Gas Turbines, Aachen University of Technology. It takes into account of the mutual influences of internal and external fluid flow and heat transfer. The strategy of the procedure is based on a multi-block-technique and a direct coupling module for fluid flow regions and solid body regions. The configuration under investigation in the present paper is based on a test design of a convective cooled turbine blade with serpentine-shaped cooling passages and cooling gas ejection at the blade tip and the trailing edge. The numerical investigations focus on secondary flow phenomena in the ducts and on the heat transfer analysis at the cooling channel walls. In the first part, the cooling channels are investigated with adiabatic smooth & ribbed walls. The calculations are carried out for the stationary and rotating configuration. Concerning the heat transfer analysis, the results of the ribbed configuration with a fixed thermal boundary condition at the walls in the stationary case are presented. Furthermore, in order to demonstrate the capability of the conjugate method to work without thermal boundary conditions, the cooling configuration is calculated including the external blade flow and the blade walls with internal and external heat transfer under typical operation conditions of gas turbines. The numerical code is used to determine the blade surface temperatures.

Effects of Guide Vanes on the Tip Heat Transfer Enhancement of a Turbine Blade

2011 ◽  
Author(s):  
Gongnan Xie ◽  
Bengt Sunde´n
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Transfer Enhancement ◽  
Turbine Blade ◽  
Pressure Loss ◽  
Transfer Enhancement ◽  
Guide Vanes ◽  
Flow And Heat Transfer ◽  
Numerical Predictions ◽  
Blade Tip

Gas turbine blade tips encounter large heat load as they are exposed to the high temperature gas. A common way to cool the blade and its tip is to design serpentine passages with 180-deg turns under the blade tip-cap inside the turbine blade. Improved internal convective cooling is therefore required to increase the blade tip life time. This paper presents numerical predictions of turbulent fluid flow and heat transfer through two-pass channels with and without guide vanes placed in the turn regions using RANS turbulence modeling. The effects of adding guide vanes on the tip-wall heat transfer enhancement and the channel pressure loss were analyzed. The guide vanes have a height identical to that of the channel. The inlet Reynolds numbers are ranging from 100,000 to 600,000. The detailed three-dimensional fluid flow and heat transfer over the tip-walls are presented. The overall performances of several two-pass channels are also evaluated and compared. It is found that the tip heat transfer coefficients of the channels with guide vanes are 10∼60% higher than that of a channel without guide vanes, while the pressure loss might be reduced when the guide vanes are properly designed and located, otherwise the pressure loss is expected to be increased severely. It is suggested that the usage of proper guide vanes is a suitable way to augment the blade tip heat transfer and improve the flow structure, but is not the most effective way compared to the augmentation by surface modifications imposed on the tip-wall directly.

A Conjugate 3-D Flow and Heat Transfer Analysis of a Thermal Barrier Cooled Turbine Guide Vane

1998 ◽  
Author(s):  
Dieter E. Bohn ◽  
Volker J. Becker
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
Guide Vane ◽  
Suction Side ◽  
Heat Transfer Analysis ◽  
Thermal Barrier ◽  
Trailing Edge ◽  
Flow And Heat Transfer ◽  
Turbine Guide Vane ◽  
Basic Configuration

This paper presents the numerical investigations of the flow and heat transfer of two configurations of a transonic turbine guide vane. The basic configuration is a vane with convection cooling. The second configuration is additionally coated with a thermal barrier consisting of ZrO2. The results are obtained with a conjugate heat transfer and flow computer code that has been developed at the Institute of Steam and Gas Turbines. Measurement data is available for the basic configuration and the computational results are compared to the experimental results. The results show very good agreement between calculated and measured vane surface temperatures. The trailing edge turns out to be subjected to high thermal loads as it is too thin to be cooled effectively. Secondary flow phenomena like the passage vortex and the corner vortex and their impact on the temperature distribution are discussed. The ZrO2 coating is calculated for a thickness of 300μm. The substrate material temperatures are lowered by about 20 K–29 K in the stagnation point area and by about 27 K–43 K in the shock area on the suction side. At the trailing edge, the coating on the suction side and on the pressure side hardly influences the metal temperature.

scholarly journals Effect of Reynolds Number and Property Variation on Fluid Flow and Heat Transfer in the Entrance Region of a Turbine Blade Internal-Cooling Channel

2005 ◽  
Vol 2005 (1) ◽  
pp. 36-44 ◽  
Author(s):  
R. Ben-Mansour ◽  
L. Al-Hadhrami
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Mass Flow Rate ◽  
Heat Transfer Rate ◽  
Turbine Blade ◽  
Flow Rate ◽  
Transfer Rate ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Flow And Heat Transfer

Internal cooling is one of the effective techniques to cool turbine blades from inside. This internal cooling is achieved by pumping a relatively cold fluid through the internal-cooling channels. These channels are fed through short channels placed at the root of the turbine blade, usually called entrance region channels. The entrance region at the root of the turbine blade usually has a different geometry than the internal-cooling channel of the blade. This study investigates numerically the fluid flow and heat transfer in one-pass smooth isothermally heated channel using the RNGk−εmodel. The effect of Reynolds number on the flow and heat transfer characteristics has been studied for two mass flow rate ratios (1/1and1/2) for the same cooling channel. The Reynolds number was varied between10 000and50 000. The study has shown that the cooling channel goes through hydrodynamic and thermal development which necessitates a detailed flow and heat transfer study to evaluate the pressure drop and heat transfer rates. For the case of unbalanced mass flow rate ratio, a maximum difference of8.9% in the heat transfer rate between the top and bottom surfaces occurs atRe=10 000while the total heat transfer rate from both surfaces is the same for the balanced mass flow rate case. The effect of temperature-dependent property variation showed a small change in the heat transfer rates when all properties were allowed to vary with temperature. However, individual effects can be significant such as the effect of density variation, which resulted in as much as9.6% reduction in the heat transfer rate.

scholarly journals Heat Transfer Analysis of Two Pass Cooling Channel of Gas Turbine Blade With Analytical Wall Function Turbulence Approach

2013 ◽  
Author(s):  
Hitoshi Arakawa ◽  
Shaohua Shen ◽  
Ryo S. Amano
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Analysis ◽  
Computational Studies ◽  
Cooling Channel ◽  
Wall Function ◽  
Square Duct ◽  
Flow And Heat Transfer ◽  
Predicting Performance ◽  
Function Models

This paper reports experimental and computational studies of flow and heat transfer through a square duct with a sharp 180 degree turn. The main purpose of this research is to study flow and heat transfer predictions of the Analytical Wall-Function (AWF). To compare the predicting performance of the AWF, the standard Log-Law Wall-Function (LWF) and Low-Reynolds-number (LRN) k-ε model were applied. Their results were also compared with the experimental results for validation. In addition, three extended forms of the AWF were tested. Computational results showed better agreement with the experimental data, especially after the turn of the channel. It was also found that the wall-function (WF) models predicted more reasonable results as Reynolds number increased. The both wall-function models predicted similar results except for separation/reattachment regions where the LWF predicted lower Nusselt number than the other models.

scholarly journals Fluid flow and heat transfer analysis of TEFC machine end regions using more realistic end-winding geometry

2019 ◽  
Vol 2019 (17) ◽  
pp. 3831-3835
Author(s):  
Salvatore La Rocca ◽  
Stephen J. Pickering ◽  
Carol N. Eastwick ◽  
Chris Gerada ◽  
Kristian Rönnberg
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Transfer Analysis ◽  
Flow And Heat Transfer

Numerical and experimental analysis of microchannel heat transfer for nanoliquid coolant using different shapes and geometries

2014 ◽  
Vol 229 (11) ◽  
pp. 2056-2065 ◽  
Author(s):  
Harry Garg ◽  
Vipender Singh Negi ◽  
Nidhi Garg ◽  
AK Lall
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Fluid Flow ◽  
Transfer Coefficient ◽  
Experimental Analysis ◽  
High Heat ◽  
Heat Transfer Analysis ◽  
Flow And Heat Transfer ◽  
High Heat Transfer ◽  
High Heat Transfer Coefficient

As part of the liquid cooling, most of the work has been done on fluid flow and heat transfer analysis for flow field. In the present work, the experimental and numerical studies of the microchannel the fluid flow and heat transfer analysis using nanoliquid coolant have been discussed. The practical aspects for increasing the high heat transfer coefficient from conventional studies and the different geometries and shapes of the microchannel are studied. The Aspect Ratio has significant effect on the microchannels and has been varied from AR 2, 4 and 8 to choose the optimum one. Three different fluids, i.e. de-ionized water, ethylene glycol, and a custom nanofluid are chosen for study. The proposed nanofluid almost interacts as another solid and has reduced thermal resistance, friction effect, and thus it almost vanishes high hot spots. Experimental analysis shows that the proposed nanofluid is excellent fluid for high rate heat removals. Moreover, the performance of the overall system is excellent in terms of high heat transfer coefficient, high thermal conductivity, and high capacity of the fluid. It has been reported that the heat transfer coefficient can be increased to 2.5 times of the water or any other fluid. It was also reported that the AR 4 rectangular-shaped channels are the optimum geometry in the Reynolds number ranging from 50 to 800 considering laminar flow. Examination and identification is based upon the practical result that includes fabrication constraints, commercial application, sealing of the system, ease of operation, and so on.

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