scholarly journals Flow and heat transfer characters in the integral internal cooling channel of a turbine blade

2019 ◽  
Vol 1369 ◽  
pp. 012006
Author(s):  
Tao Guo ◽  
Huiren Zhu ◽  
Zhixiang Zhou
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Flow And Heat Transfer

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.

Experimental Study on Flow Behavior and Heat Transfer Enhancement with Distinct Dimpled Gas Turbine Blade Internal Cooling Channel

2021 ◽  
pp. 1-28
Author(s):  
Farah Nazifa Nourin ◽  
Ryoichi S. Amano
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Enhancement ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Thermal Performance ◽  
Diameter Ratio ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Transfer Enhancement

Abstract The study presents the investigation on heat transfer distribution along a gas turbine blade internal cooling channel. Six different cases were considered in this study, using the smooth surface channel as a baseline. Three different dimples depth-to-diameter ratios with 0.1, 0.25, and 0.50 were considered. Different combinations of partial spherical and leaf dimples were also studied with the Reynolds numbers of 6,000, 20,000, 30,000, 40,000, and 50,000. In addition to the experimental investigation, the numerical study was conducted using Large Eddy Simulation (LES) to validate the data. It was found that the highest depth-to-diameter ratio showed the highest heat transfer rate. However, there is a penalty for increased pressure drop. The highest pressure drop affects the overall thermal performance of the cooling channel. The results showed that the leaf dimpled surface is the best cooling channel based on the highest Reynolds number's heat transfer enhancement and friction factor. However, at the lowest Reynolds number, partial spherical dimples with a 0.25 depth to diameter ratio showed the highest thermal performance.

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.

scholarly journals A Computational Visualization of Three Dimensional Flow: Finding Optimum Heat Transfer and Pressure Drop Characteristics From Short Cross-Pin Arrays and Comparison With Two Dimensional Calculations

1999 ◽  
Author(s):  
E. E. Donahoo ◽  
C. Camci ◽  
A. K. Kulkarni ◽  
A. D. Belegundu
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Structural Integrity ◽  
Turbine Blades ◽  
Circular Cross Section ◽  
Internal Cooling ◽  
Flow And Heat Transfer ◽  
High Heat Transfer ◽  
Spacing Ratio ◽  
Cooling Passage

There are many heat transfer augmentation methods that are employed in turbine blade design, such as impingement cooling, film cooling, serpentine passages, trip strips, vortex chambers, and pin fins. The use of crosspins in the trailing edge section of turbine blades is commonly a viable option due to their ability to promote turbulence as well as supply structural integrity and stiffness to the blade itself. Numerous crosspin shapes and arrangements are possible, but only certain configurations offer high heat transfer capability while maintaining taw total pressure loss. This study preseots results from 3-D numerical simulations of airflow through a turbine blade internal cooling passage. The simulations model viscous flow and heat transfer over full crosspins of circular cross-section with fixed height-to-diameter ratio of 0.5, fixed transverse-to-diameter spacing ratio of 1.5, and varying streamwise spacing. Preliminary analysis indicates that endwall effects dominate the flow and heat transfer at lower Reynolds numbers. The flow dynamics involved with the relative dose proximity of the endwalls for such short crosspins have a definite influeoce on crosspin efficiency for downstream rows.

Large Eddy Simulation of Flow and Heat Transfer in the Developing Flow Region of a Rotating Gas Turbine Blade Internal Cooling Duct With Coriolis and Buoyancy Forces

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Evan A. Sewall ◽  
Danesh K. Tafti
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Flow Region ◽  
Internal Cooling ◽  
Heat Transfer Augmentation ◽  
Flow And Heat Transfer ◽  
Buoyancy Parameter ◽  
Developing Flow ◽  
Large Eddy

The problem of accurately predicting the flow and heat transfer in the ribbed internal cooling duct of a rotating gas turbine blade is addressed with the use of large eddy simulations (LES). Four calculations of the developing flow region of a rotating duct with ribs on opposite walls are used to study changes in the buoyancy parameter at a constant rotation rate. The Reynolds number is 20,000, the rotation number is 0.3, and the buoyancy parameter is varied between 0.00, 0.25, 0.45, and 0.65. Previous experimental studies have noted that leading wall heat transfer augmentation decreases as the buoyancy parameter increases with low buoyancy, but heat transfer then increases with high buoyancy. However, no consistent physical explanation has been given in the literature. The LES results from this study show that the initial decrease in augmentation with buoyancy is a result of larger separated regions at the leading wall. However, as the separated region spans the full pitch between ribs with an increase in buoyancy parameter, it leads to increased turbulence and increased entrainment of mainstream fluid, which is redirected toward the leading wall by the presence of a rib. The impinging mainstream fluid results in heat transfer augmentation in the region immediately upstream of a rib. The results obtained from this study are in very good agreement with previous experimental results.

Flow and Heat Transfer Analysis of Turbine Blade Cooling Passages Using Network Method

2012 ◽  
Author(s):  
Mohammad Alizadeh ◽  
Ali Izadi ◽  
Alireza Fathi ◽  
Hiwa Khaledi
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Turbine Blade ◽  
Numerical Data ◽  
Internal Cooling ◽  
Turbine Blade Cooling ◽  
Blade Cooling ◽  
Flow And Heat Transfer ◽  
Network Method ◽  
Cooling Passage

Modern turbine blades are cooled by air flowing through internal cooling passages. Three-Dimensional numerical simulation of these blade cooling passages is too time-consuming because of their complex geometries. These geometrical complexities exist as a result of using various kinds of cooling technologies such as rib turbulators (inline, staggered, or inclined ribs), pin fin, 90 and 180 degree turns (both sharp and gradual turns, with and without turbulators), finned passage, by-pass flow and tip cap impingement. One possible solution to simulate such sophisticated passages is to use the one-dimensional network method, which is presented in the current work. Turbine blade cooling channels are flow passages having multiple inlets and exits. The present in-house developed solver uses a network method for analyzing such a complicated flow pattern. In this method, cooling system is represented by a network of elements connected together at different nodes. Using assumed wall temperature, internal flow and heat transfer is calculated. The final goal of this computation is a set of boundary conditions for conjugate blade heat transfer simulation (coolant side boundary conditions). For validation, it is required to use experimental data that include temperature distribution of blade coolant-side walls. Since there is no experimental work with such data in the open literature, numerical computation is validated using available analytical and published numerical data. Calculated results agree well with analytical and numerical data. In order to exhibit the potential capabilities of the developed code, flow and heat transfer in a complicated internal cooling passage of a typical vane are investigated using the network method.

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