Numerical Study on the Influence of the Trailing Edge Overflow Holes on the Flow and Heat Transfer of the Inner Cooling Passage on the Trailing Edge of the Turbine Blade

2019 ◽  
pp. 1717-1729
Author(s):  
Shun Zhao ◽  
Guanghua Zheng ◽  
Chengcheng Hui
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Numerical Study ◽  
Trailing Edge ◽  
Flow And Heat Transfer ◽  
Cooling Passage

Numerical Study of Heat Transfer and Cooling Effectiveness on a Flat-Tip Turbine Blade

2013 ◽  
Author(s):  
Qihe Huang ◽  
Jiao Wang ◽  
Lei He ◽  
Qiang Xu
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Film Cooling ◽  
Numerical Study ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Cooling Effectiveness ◽  
Blowing Ratio ◽  
Flow And Heat Transfer ◽  
Blade Tip

A numerical study is performed to simulate the tip leakage flow and heat transfer on the first stage rotor blade tip of GE-E3 turbine, which represents a modern gas turbine blade geometry. Calculations consist of the flat blade tip without and with film cooling. For the flat tip without film cooling case, in order to investigate the effect of tip gap clearance on the leakage flow and heat transfer on the blade tip, three different tip gap clearances of 1.0%, 1.5% and 2.5% of the blade span are considered. And to assess the performance of the turbulence models in correctly predicting the blade tip heat transfer, the simulations have been performed by using four different models (the standard k-ε, the RNG k-ε, the standard k-ω and the SST models), and the comparison shows that the standard k-ω model provides the best results. All the calculations of the flat tip without film cooling have been compared and validated with the experimental data of Azad[1] and the predictions of Yang[2]. For the flat tip with film cooling case, three different blowing ratio (M = 0.5, 1.0, and 1.5) have been studied to the influence on the leakage flow in tip gap and the cooling effectiveness on the blade tip. Tip film cooling can largely reduce the overall heat transfer on the tip. And the blowing ratio M = 1.0, the cooling effect for the blade tip is the best.

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.

Flow and Heat Transfer in a Triple-Impingement Configuration for Trailing-Edge Cooling

2012 ◽  
Author(s):  
J. Liu ◽  
A. Weaver ◽  
T. I-P. Shih ◽  
J. Klinger ◽  
B. Heneveld ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Temperature ◽  
Trailing Edge ◽  
Impingement Cooling ◽  
Hot Gas ◽  
Flow And Heat Transfer ◽  
Sst Turbulence Model ◽  
Cooling Passage ◽  
Turbine Airfoils ◽  
The Heat Transfer Coefficient

The trailing-edge region of turbine airfoils is difficult to cool. In this study, CFD conjugate analysis based on the shear-stress transport (SST) turbulence model is used to study the flow and heat transfer in a triple-impingement cooling configuration. Parameters studied include the pressure drop across the configuration (1, 2, 3, 4, and 5 bars), and the heat transfer coefficient on the hot-gas side (2,000, 4,000, and 6,000 W/m2-K). In all cases with conjugate analysis, the temperature of the coolant at the inlet of the cooling passage is 673 K, the external hot-gas temperature is 1,755 K, and the static pressure at the exit of cooling passage is 25 bars. Simulations were also performed in which the temperature of the cooling-passage wall is kept constant at 1,173 K. Results are generated to show the nature of the flow induced by the triple impingement and how that flow affects heat transfer to the turbine material.

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.

Unsteady CFD Analysis of Turbulent Flow and Heat Transfer in a Gas Turbine Blade Trailing Edge Subjected to Rotation

2012 ◽  
Author(s):  
Domenico Borello ◽  
Giovanni Delibra ◽  
Cosimo Bianchini ◽  
Antonio Andreini
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Heated Surface ◽  
Heat Removal ◽  
Gas Turbine Blade ◽  
Trailing Edge ◽  
Flow And Heat Transfer ◽  
The Impact

Internal cooling of gas turbine blade represents a challenging task involving several different phenomena as, among others, highly three-dimensional unsteady fluid flow, efficient heat transfer and structural design. This paper focuses on the analysis of the turbulent flow and heat transfer inside a typical wedge–shaped trailing edge cooling duct of a gas turbine blade. In the configuration under scrutiny the coolant flows inside the duct in radial direction and it leaves the blade through the trailing edge after a 90 deg turning. At first an analysis of the flow and thermal fields in stationary conditions was carried out. Then the effects of rotational motion were investigated for a rotation number of 0.275. The rotation axis here considered is normal to the inflow and outflow bulk velocity, representing schematically a highly loaded blade configuration. The work aimed to i) analyse the dynamic of the vortical structures under the influence of strong body forces and the constraints induced by the internal geometry and ii) to study the impact of such motions on the mechanisms of heat removal. The final aim was to verify the design of the equipment and to detect the possible presence of regions subjected to high thermal loads. The analysis is carried out using the well assessed open source code OpenFOAM written in C++ and widely validated by several scientists and researchers around the world. The unsteadiness of the flow inside the trailing edge required to adopt models that accurately reconstructed the flow field. As the computational costs associated to LES (especially in the near wall regions) largely exceed the available resources, we chose for the simulation the SAS model of Menter, that was validated in a series of benchmark and industrially relevant test cases and allowed to reconstruct a part of the turbulence spectra through a scale-adaptive mechanism. Assessment of the obtained results with steady-state k-ω SST computations and available experimental results was carried out. The present analysis demonstrated that a strong unsteadiness develops inside the trailing edge and that the rotation generated strong secondary motions that enhanced the dynamic of heat removal, leading to a less severe temperature distribution on the heated surface w.r.t the non rotating case.

Numerical Study on Flow and Heat Transfer Characteristics of Pin-Fins With Different Shapes

2019 ◽  
Author(s):  
Wei Jin ◽  
Ning Jia ◽  
Junmei Wu ◽  
Jiang Lei ◽  
Lin Liu
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Numerical Study ◽  
Heated Surface ◽  
Transfer Effect ◽  
Enhancement Effect ◽  
Trailing Edge ◽  
Pin Fin ◽  
Flow And Heat Transfer ◽  
Pin Fins

Abstract Equipping pin-fins in the blade trailing edge is an significant method for enhancing heat transfer. In order to obtain a geometry of pin-fins with good heat transfer effect and small friction factor, six pin-fins (circular, elliptic, oblong, teardrop, lancet and NACA) are selected. The flow and heat transfer features of the rectangular channel with the staggered pin-fins were numerically studied through FLUENT software. The channels with different pin-fins have the same relative spanwise pitch (S/D = 2.5) and streamwise pitch (X/D = 2.5), and the range of Reynolds number is 5×103 to 3×104. The applicability and accuracy of five turbulence models (Standard k-ε, Realizable k-ε, RNG k-ε, Standard k-ω and SST k-ω) are checked by comparing the numerically predicted results with the experimental from literature. It is found that the Realizable k-ε model is better at capturing the microstructure of flow field and has higher precision in predicting the averaged Nusselt number on the heated surface. For the six pin-fins, the leading edge is surrounded by a “U-shaped” strong heat exchange zone, but the vortex systems in the trailing edge are different from each other. Compared to the circular pin-fin, the oblong pin-fin has the best heat transfer enhancement effect, but the friction factor of channel is also larger. While the NACA pin-fin has the lowest friction factor, and the heat transfer effect is second only to the oblong. NACA pin-fin may be applied in blade trailing edge cooling by further optimizing the relative position of the pin-fins in the channel.

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