scholarly journals Micro scale jet impingement cooling and its efficacy on turbine vanes : a numerical study

2021 ◽  
Author(s):  
Santhiya Jayaraman
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Leading Edge ◽  
Jet Impingement ◽  
3D Analysis ◽  
Transfer Rates ◽  
Impingement Cooling ◽  
Micro Scale ◽  
Turbine Vane ◽  
Nozzle Configuration

A numerical analysis of effectiveness of micro-jet impingement cooling on leading edge of a turbine vane is presented. An axisymmetric single round jet was assessed for its ability and consistency as a preliminary study including the investigation of parameters influencing the heat transfer distribution. The analysis revealed that an increase in Nusselt number was attributed to increase in Reynolds number, decrease in jet diameter and H/D < 3. Significant improvement in heat transfer was observed for tapering nozzle configuration. The study was then further expanded to 3D analysis of leading edge cooling of turbine vane. Effect of nozzle diameter to micro-scale was studied, which showed 65% enhancement in the heat transfer rates.

scholarly journals Micro scale jet impingement cooling and its efficacy on turbine vanes : a numerical study

2021 ◽  
Author(s):  
Santhiya Jayaraman
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Leading Edge ◽  
Jet Impingement ◽  
3D Analysis ◽  
Transfer Rates ◽  
Impingement Cooling ◽  
Micro Scale ◽  
Turbine Vane ◽  
Nozzle Configuration

A numerical analysis of effectiveness of micro-jet impingement cooling on leading edge of a turbine vane is presented. An axisymmetric single round jet was assessed for its ability and consistency as a preliminary study including the investigation of parameters influencing the heat transfer distribution. The analysis revealed that an increase in Nusselt number was attributed to increase in Reynolds number, decrease in jet diameter and H/D < 3. Significant improvement in heat transfer was observed for tapering nozzle configuration. The study was then further expanded to 3D analysis of leading edge cooling of turbine vane. Effect of nozzle diameter to micro-scale was studied, which showed 65% enhancement in the heat transfer rates.

Numerical Study of Flow and Heat Transfer of Impingement Cooling on Model of Turbine Blade Leading Edge

2010 ◽  
Author(s):  
Zhao Liu ◽  
Zhenping Feng ◽  
Liming Song
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Numerical Study ◽  
Leading Edge ◽  
Jet Impingement ◽  
Target Surface ◽  
Nozzle Diameter ◽  
Impingement Cooling ◽  
Jet Nozzle ◽  
Blade Leading Edge

In this paper a numerical simulation is performed to simulate the impingement cooling on internal leading edge region, which is stretched by the middle cross section of the first stage rotor blade of GE-E3 engine high pressure turbine, and in the condition that jets flow is ejected from a row of four different diameter circular nozzles. The relative performances of three versions of turbulence models including the RNG κ-ε model, the standard κ-ω model and the SST κ-ω model in the simulation of a row of circle jet impingement heat transfer are compared with available experimental data. The results show that SST κ-ω model is the best one based on simulation accuracy. Then the SST κ-ω model is adopted for the simulation. The grid independence study is also carried out by using the Richardson extrapolation method. A single array of circle jets is arranged to investigate the impingement cooling and its effectiveness. Four different jet nozzle diameters are studied and seven different inlet flow Mach numbers of each jet nozzle diameter are calculated. The influence of the ratio of the spacing of jet nozzle from the target surface to the jet nozzle diameter on impingement cooling is also studied, in case of a constant ratio of jet spacing to jet nozzle diameter in different jet nozzle diameters. The results indicate that the heat transfer coefficient on the turbine blade leading edge increases with the increase of jet Mach number and jet nozzle diameter, the spanwise area weight average Nusselt number decreases with the increase of the ratio of the spacing of jet nozzle from the target surface to jet nozzle diameter, and a lower ratio of spacing of jet nozzle from the target surface to the jet nozzle diameter is desirable to improve the performance of impingement cooling on turbine leading edge.

scholarly journals A Numerical Study Of Micro-Jet Impingement Cooling Inside A High Pressure Turbine Vane

2021 ◽  
Author(s):  
Marcel L. De Paz
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Numerical Study ◽  
Three Dimensional ◽  
Leading Edge ◽  
Jet Impingement ◽  
High Pressure Turbine ◽  
Impingement Cooling ◽  
Average Heat ◽  
Heated Area

A thorough numerical analysis of micro-impingement cooling for application in high pressure turbine vanes is presented. The fundamental flow of an axisymmetric jet is first modeled and studied to ascertain the validity of the results. Subsequent, a fully three dimensional curved vane is modeled with an in-line impinging array of jet diamters 0.5mm. The analysis reveals that spent air collects with increasing streamwise distance from the leading edge, thereby increasing jet exit velocities across the array. For all cases studied, an increase in jet to target spacing increased the overall Reynolds number of the array, but decreased the average heat transfer rate. Micro diameters of 0.25mm were subsequently studied for full vane geometry. For a given mass flow per unit of heated area, the micro-jets considerably increased the average heat transfer by 63%. Similar enhancements were obtained at a fixed pressure drop percentage, and for a desired average heat transfer.

scholarly journals A Numerical Study Of Micro-Jet Impingement Cooling Inside A High Pressure Turbine Vane

2021 ◽  
Author(s):  
Marcel L. De Paz
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Numerical Study ◽  
Three Dimensional ◽  
Leading Edge ◽  
Jet Impingement ◽  
High Pressure Turbine ◽  
Impingement Cooling ◽  
Average Heat ◽  
Heated Area

A thorough numerical analysis of micro-impingement cooling for application in high pressure turbine vanes is presented. The fundamental flow of an axisymmetric jet is first modeled and studied to ascertain the validity of the results. Subsequent, a fully three dimensional curved vane is modeled with an in-line impinging array of jet diamters 0.5mm. The analysis reveals that spent air collects with increasing streamwise distance from the leading edge, thereby increasing jet exit velocities across the array. For all cases studied, an increase in jet to target spacing increased the overall Reynolds number of the array, but decreased the average heat transfer rate. Micro diameters of 0.25mm were subsequently studied for full vane geometry. For a given mass flow per unit of heated area, the micro-jets considerably increased the average heat transfer by 63%. Similar enhancements were obtained at a fixed pressure drop percentage, and for a desired average heat transfer.

scholarly journals Numerical heat transfer analysis of micro-scale jet-impingement cooling in a high-pressure turbine vane

2021 ◽  
Author(s):  
Karan Anand
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Jet Impingement ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Heat Transfer Analysis ◽  
Transfer Rates ◽  
Numerical Heat Transfer ◽  
Turbine Vane ◽  
Single Jet

This research provides a computational analysis of heat transfer due to micro jet-impingement inside a gas turbine vane. A preliminary-parametric analysis of axisymmetric single jet was reported to better understand micro jet-impingement. In general, it was seen that as the Reynolds number increased the Nusselt number values increased. The jet to target spacing had a considerably lower impact on the heat transfer rates. Around 30% improvement was seen by reducing the diameter to half while changing the shape to an ellipse saw 20.8% improvement in Nusselt value. The numerical investigation was then followed by studying the heat transfer characteristics in a three-dimensional, actual-shaped turbine vane. Effects of jet inclination showed enhanced mixing and secondary heat transfer peaks. The effect of reducing the diameter of the jets to 0.125 mm yielded 55% heat transfer improvements compared to 0.51 mm; the tapering effect also enhanced the local heat transfer values as local velocities at jet exit increased.

Experimental and Numerical Study of Array Jet Impingement Cooling on a Leading Edge Curved Surface

2021 ◽  
Author(s):  
Husam Zawati ◽  
Jorge Torres ◽  
Erik Fernandez ◽  
Jose Rodriguez ◽  
Jayanta Kapat
Keyword(s):  
Numerical Study ◽  
Leading Edge ◽  
Jet Impingement ◽  
Curved Surface ◽  
Impingement Cooling

Evaluation of CFD Simulations of Film Cooling Performance in the Showerhead Region of a Turbine Vane Including Conjugate Effects

2012 ◽  
Author(s):  
Thomas E. Dyson ◽  
David G. Bogard ◽  
Sean D. Bradshaw
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Leading Edge ◽  
External Boundary ◽  
Experimental Measurements ◽  
Impingement Cooling ◽  
Heat Transfer Augmentation ◽  
Turbine Vane ◽  
Sst Turbulence Model ◽  
Investigate Heat Transfer

Computational simulations using RANS and the k-ω SST turbulence model were performed to complement experimental measurements of overall cooling effectiveness and adiabatic film effectiveness for a film cooled turbine vane airfoil. Particular attention was placed on the showerhead. The design made use of five rows of showerhead holes and a single gill row on both pressure and suction sides. The simulated geometry also included the internal impingement cooling configuration. Internal and external boundary conditions were matched to experiments using the same vane model. To correctly simulate conjugate heat transfer effects, the experimental vane model was constructed to match the Biot number for engine conditions. Computational predictions of the overall and adiabatic effectiveness were compared to experimental measurements from both the conducting vane and a model constructed from low conductivity foam. The results show that the k-ω SST RANS model over-predicts both adiabatic and overall effectiveness due in part to limited jet diffusion. The simulations were also used to investigate heat transfer augmentation, which is difficult to measure experimentally in the showerhead region. The results showed substantial augmentation of 1.5 or more over large portions of the leading edge, with many areas exceeding 2.0. However, the simulations also showed a reduction in heat transfer (i.e., hf/h0 < 1) for locations beneath the coolant jets. This result was likely due to Taw being an inappropriate driving temperature for separated jets.

Numerical Study on Flow and Heat Transfer Characteristics of Jet Impingement Cooling

2011 ◽  
Vol 148-149 ◽  
pp. 680-683
Author(s):  
Run Peng Sun ◽  
Wei Bing Zhu ◽  
Hong Chen ◽  
Chang Jiang Chen
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Numerical Study ◽  
Cross Flow ◽  
Jet Impingement ◽  
Local Heat Transfer ◽  
Transfer Characteristic ◽  
Heat Transfer Characteristics ◽  
Impingement Cooling ◽  
Transfer Characteristics

Three-dimensional numerical study is conducted to investigate the heat transfer characteristics for the flow impingement cooling in the narrow passage based on cooling technology of turbine blade.The effects of the jet Reynolds number, impingement distance and initial cross-flow on heat transfer characteristic are investigated.Results show that when other parameters remain unchanged local heat transfer coefficient increases with increase of jet Reynolds number；overall heat transfer effect is reduced by initial cross-flow；there is an optimal distance to the best effect of heat transfer.

Predictions of Thermal and Hydrodynamic Characteristics of a Single Circular Micro-Jet Impinging on a Flat Plate

2008 ◽  
Author(s):  
Marcel Le´on De Paz ◽  
B. A. Jubran
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Flat Plate ◽  
Reference Model ◽  
Preliminary Investigation ◽  
Jet Impingement ◽  
Hydrodynamic Characteristics ◽  
Transfer Rates ◽  
Impingement Cooling ◽  
3 Dimensional

Jet impingement cooling remains one of the key methods in various high-end cooling applications as it can induce higher heat transfer rates. The objective of this preliminary investigation is to shed some light on micro-impingement cooling and assess the accuracy for a future 3-dimensional turbine blade model. For the purpose of this study, several micro-jet impingement cases are modeled in Gambit and iterated with Fluent. The reference model consists of a single 500μm cylindrical nozzle impinging on a constant temperature flat plate. Conducive results were found on the effects of turbulence model, Reynolds number, and H/D ratio for the Nusselt distribution on the flat plate. The Reynolds numbers iterated were: 2000, 3000, 4000, 5000, and 6000. The different H/D ratios modeled were: 6, 5, 4, 3, 2, 1. In general, it was observed that a higher Reynolds number increased the heat transfer on the plate, but the jet to target spacing had no significant impact on it. All results were validated via comparison with several published experimental data, the deviation margins indicated a good agreement.

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