Conjugate Heat Transfer Analysis of an Engine Internal Cavity

2000 ◽  
Author(s):  
A. Montenay ◽  
L. Paté ◽  
J. M. Duboué
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Interaction Model ◽  
Heat Transfer Analysis ◽  
Navier Stokes ◽  
Internal Cavity ◽  
Internal Cooling ◽  
Solid Media ◽  
Coupling Procedure ◽  
And Performance

The analysis of heat transfer in engine cavities or blade internal cooling systems is one of the most challenging work for aircraft engines designers for two main reasons. Firstly, the efficiency of such systems has a direct influence on both life and performance of these engines. Secondly, the available tools to predict heat transfer in both solid parts and surrounding cooling gases, i.e. Navier Stokes and conduction codes, are often used independently. An interaction model between the fluid and solid media is generally required and remains a difficult issue in engine configurations. A coupling procedure between a Navier-Stokes code and a conduction solver is therefore the only way to achieve heat transfer predictions in all flow situations. The objective of this work is to present such a procedure, which has been developed at Snecma and based on a Finite Volume Navier-Stokes code and a commercial Finite Element solver. The first application showed in the paper demontrates, with an uncoupled calculation that the Navier-Stokes code MSD, from ONERA, is able to predict heat transfer with an acceptable accuracy. The discretization used in the solid to predict heat conduction is briefly presented. Then the steady state coupling procedure is exposed and validated with an analytical solution. Finally, a conjugate heat transfer computation in a rotor/rotor cavity of a real engine, with rotating solid disks, is described in detail.

Conjugate Heat Transfer Analysis to Assess Overall Cooling Effectiveness of High Pressure Turbine Nozzle With Optimized Film Cooling Hole Arrangements

2019 ◽  
Author(s):  
Young Seok Kang ◽  
Dong-Ho Rhee ◽  
Sanga Lee ◽  
Bong Jun Cha
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Analysis ◽  
Internal Cooling ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Baseline Design ◽  
Pressure Surface

Abstract Conjugate heat transfer analysis method has been highlighted for predicting heat exchange between fluid domain and solid domain inside high-pressure turbines, which are exposed to very harsh operating conditions. Then it is able to assess the overall cooling effectiveness considering both internal cooling and external film cooling at the cooled turbine design step. In this study, high-pressure turbine nozzles, which have three different film cooling holes arrangements, were numerically simulated with conjugate heat transfer analysis method for predicting overall cooling effectiveness. The film cooling holes distributed over the nozzle pressure surface were optimized by minimizing the peak temperature, temperature deviation. Additional internal cooling components such as pedestals and rectangular rib turbulators were modeled inside the cooling passages for more efficient heat transfer. The real engine conditions were given for boundary conditions to fluid and solid domains for conjugate heat transfer analysis. Hot combustion gas properties such as specific heat at constant pressure and other transport properties were given as functions of temperature. Also, the conductivity of Inconel 718 was also given as a function of temperature to solve the heat equation in the nozzle solid domain. Conjugate heat transfer analysis results showed that optimized designs showed better cooling performance, especially on the pressure surface due to proper staggering and spacing hole-rows compared to the baseline design. The overall cooling performances were offset from the adiabatic film cooling effectiveness. Locally concentrated heat transfer and corresponding high cooling effectiveness region appeared where internal cooling effects were overlapped in the optimized designs. Also, conjugate heat transfer analysis results for the optimized designs showed more uniform contours of the overall cooling effectiveness compared to the baseline design. By varying the coolant mass flow rate, it was observed that pressure surface was more sensitive to the coolant mass flow rate than nozzle leading edge stagnation region and suction surface. The CHT results showed that optimized designs to improve the adiabatic film cooling effectiveness also have better overall cooling effectiveness.

Conjugate Heat Transfer Calculations on GT Rotor Blade for Industrial Applications: Part I—Equivalent Internal Fluid Network Setup and Procedure Description

2012 ◽  
Author(s):  
A. Bonini ◽  
A. Andreini ◽  
C. Carcasci ◽  
B. Facchini ◽  
A. Ciani ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Rotor Blade ◽  
Conjugate Heat Transfer ◽  
Cooling System ◽  
Heat Transfer Analysis ◽  
Metallographic Analysis ◽  
Internal Cooling ◽  
Continuous Increase ◽  
Fluid Network

Gas turbine design has been characterized over the years by a continuous increase of the maximum cycle temperature, justified by a corresponding increase of cycle efficiency and power output. In such way turbine components heat load management has become a compulsory activity and then, a reliable procedure to evaluate the blades and vanes metal temperatures, is, nowadays, a crucial aspect for a safe components design. This two part work presents a three-dimensional conjugate heat transfer procedure developed in the framework of an internal research project of GE Oil & Gas. The procedure, applied to the first rotor blade of the MS5002E gas turbine, consists of a conjugate heat transfer analysis in which the internal cooling system was modeled by an in-house one dimensional thermo-fluid network solver, the external heat loads and pressure distribution have been evaluated through 3D CFD and the heat conduction in the solid is carried out through a 3D FEM solution. The first part of this work is focused on the description of the procedures in terms of set up of the equivalent fluid network model of internal cooling system and its tuning through experimental measurements of blade flow function. A first computation of blade metal temperature was obtained by coupling with CFD computations carried out on a de-featured geometry of the blade. Achieved results are compared with the data of a metallographic analysis performed on a blade operated on an actual engine. Some discrepancies are observed between datasets, suggesting the necessity to improve the models, mainly from the CFD side.

Conjugate Heat Transfer Methodology for Thermal Design and Verification of Gas Turbine Cooled Components

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Lorenzo Winchler ◽  
Antonio Andreini ◽  
Bruno Facchini ◽  
Luca Andrei ◽  
Alessio Bonini ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Conjugate Heat Transfer ◽  
Cooling System ◽  
Measurement Data ◽  
Thermal Design ◽  
Heat Transfer Analysis ◽  
Internal Cooling ◽  
Cfd Analysis ◽  
Continuous Increase

Gas turbine design has been characterized over the years by a continuous increase of the maximum cycle temperature, justified by a corresponding increase of cycle efficiency and power output. In such way, turbine components heat load management has become a compulsory activity, and then, a reliable procedure to evaluate the blades and vanes metal temperatures is, nowadays, a crucial aspect for a safe components design. In the framework of the design and validation process of high pressure turbine cooled components of the BHGE NovaLTTM 16 gas turbine, a decoupled methodology for conjugate heat transfer prediction has been applied and validated against measurement data. The procedure consists of a conjugate heat transfer analysis in which the internal cooling system (for both airfoils and platforms) is modeled by an in-house one-dimensional thermo-fluid network solver, the external heat loads and pressure distribution are evaluated through 3D computational fluid dynamics (CFD) analysis and the heat conduction in the solid is carried out through a 3D finite element method (FEM) solution. Film cooling effect has been treated by means of a dedicated CFD analysis, implementing a source term approach. Predicted metal temperatures are finally compared with measurements from an extensive test campaign of the engine in order to validate the presented procedure.

Computational Analysis of Conjugate Heat Transfer in Gaseous Micro Channels

2013 ◽  
Author(s):  
Giulio Croce ◽  
Olga Rovenskaya ◽  
Paola D’Agaro
Keyword(s):  
Heat Transfer ◽  
Compressible Flows ◽  
Conjugate Heat Transfer ◽  
Computational Analysis ◽  
Slip Flow ◽  
Heat Transfer Analysis ◽  
Navier Stokes ◽  
Jump Model ◽  
Micro Channels ◽  
Slip Flow Regime

A fully conjugate heat transfer analysis of gaseous flow, within slip flow regime, in short microchannel is presented. A Navier Stokes code, coupled with Maxwell and Smoluchowski slip and temperature jump model, is adopted. Due to the link between temperature and velocity field in highly compressible flows, results are presented for Nusselt number, heat sink thermal resistance and resulting wall temperature as well as Mach number profiles for different conditions, commenting on the relative importance of wall conduction, rarefaction and compressibility. Compressibility plays a major role, and the reduction in heat transfer rate due to axial conduction is quite remarkable.

Conjugate Heat Transfer Analysis for Laminated Cooling Effectiveness: Part A — Effects of Surface Curvature

2016 ◽  
Author(s):  
Weilun Zhou ◽  
Qinghua Deng ◽  
Zhenping Feng
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Film Cooling ◽  
Pressure Loss ◽  
Conjugate Heat Transfer ◽  
Convex Surface ◽  
Heat Transfer Analysis ◽  
Internal Cooling ◽  
Cooling Effectiveness ◽  
Blowing Ratio

The laminated cooling or multi-layered impingement-effusion cooling, which originates from combustor liner cooling, combines impingement jet, rib-roughed and film cooling and results in a high overall cooling effectiveness. It’s believed to be a promising gas turbine blade cooling technique. In this paper, conjugate heat transfer analysis that has been validated by the experimental results was carried out for five laminated cooling models with different surface curvatures at a certain range of blowing ratio. The numerical results show that the curvature and blowing ratio have crucial effects on laminated cooling effectiveness. High blowing ratio results in a better overall cooling effectiveness for flat plate and concave surface, while the moderate blowing ratio performances better on convex surface. Film cooling has an interaction with the internal convective and impingement cooling, thus the optimal cooling effectiveness of laminated cooling is achieved at the condition that the improvement of internal cooling counteracts the deterioration of film cooling, instead of the condition that film cooling or internal cooling reaches the maximum respectively. Moreover, concave surfaces have the higher pressure loss in the whole range of blowing ratio, while convex surfaces have lower pressure loss than flat plate due to the turbulence intensity of external flow.

Conjugate Heat Transfer Analysis of a Rotor Blade With Rib-Roughened Internal Cooling Passages

2005 ◽  
Author(s):  
Toshihiko Takahashi ◽  
Kazunori Watanabe ◽  
Takayuki Sakai
Keyword(s):  
Heat Transfer ◽  
Temperature Profile ◽  
Rotor Blade ◽  
Conjugate Heat Transfer ◽  
Numerical Procedure ◽  
Heat Transfer Analysis ◽  
Internal Cooling ◽  
Flow Calculation ◽  
One Dimensional ◽  
Rib Roughened

In order to predict temperature distribution of a rotor blade in a gas turbine on a rated condition, numerical analyses of conjugate heat transfer of the internally cooled blade were conducted. The target blade has rib-roughened internal cooling passages. Three-dimensional steady-state numerical analysis was executed with one-dimensional thermo-flow calculation of internal cooling by means of thermal conjugation of inside and outside fields of the blade, which consists of convection heat transfer around the blade, thermal conduction of the blade material and internal cooling. The one-dimensional thermo-flow calculation for the internal cooling was conducted with correlations of friction and heat transfer in rib-roughened channels, and combined with the 3-D analysis of the blade. The present prediction of the temperature profile on the blade coincides with the distinctive features of damage on actual ex-service blades. Moreover, that predicted temperature profile is in agreement with local temperature estimated by using the material of the actual ex-service blades. Influences of distribution of inlet gas temperature and of cooling conditions on the blade temperature were also investigated by using the present numerical procedure.

Computational Analysis of Conjugate Heat Transfer in Gaseous Microchannels

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Giulio Croce ◽  
Olga Rovenskaya ◽  
Paola D'Agaro
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Mach Number ◽  
Heat Sink ◽  
Conjugate Heat Transfer ◽  
Stokes Equations ◽  
Heat Transfer Analysis ◽  
Navier Stokes ◽  
Flow Conditions ◽  
Navier Stokes Equations

A fully conjugate heat transfer analysis of gaseous flow in short microchannels is presented. Navier–Stokes equations, coupled with Maxwell and Smoluchowski slip and temperature jump boundary conditions, are used for numerical analysis. Results are presented in terms of Nusselt number, heat sink thermal resistance, and resulting wall temperature as well as Mach number profiles for different flow conditions. The comparative importance of wall conduction, rarefaction, and compressibility are discussed. It was found that compressibility plays a major role. Although a significant penalization in the Nusselt number, due to conjugate heat transfer effect, is observed even for a small value of solid conductivity, the performances in terms of heat sink efficiency are essentially a function only of the Mach number.

Conjugate Heat Transfer Analysis of a Cooled Turbine Vane Using the V2F Turbulence Model

2006 ◽  
Vol 129 (4) ◽  
pp. 773-781 ◽  
Author(s):  
Jiang Luo ◽  
Eli H. Razinsky
Keyword(s):  
Heat Transfer ◽  
Turbulence Model ◽  
Conjugate Heat Transfer ◽  
Solid Metal ◽  
Operating Conditions ◽  
Metal Temperature ◽  
Heat Transfer Analysis ◽  
Turbulent Heat Transfer ◽  
Internal Cooling ◽  
Turbine Vane

The conjugate heat transfer methodology has been employed to predict the flow and thermal properties including the metal temperature of a NASA turbine vane at three operating conditions. The turbine vane was cooled internally by air flowing through ten round pipes. The conjugate heat transfer methodology allows a simultaneous solution of aerodynamics and heat transfer in the external hot gas and the internal cooling passages and conduction within the solid metal, eliminating the need for multiple/decoupled solutions in a typical industry design process. The model of about 3 million computational meshes includes the gas path and the internal cooling channels, comprising hexa cells, and the solid metal comprising hexa and prism cells. The predicted aerodynamic loadings were found to be in close agreement with the data for all the cases. The predicted metal temperature, external, and internal heat transfer distributions at the midspan compared well with the measurement. The differences in the heat transfer rates and metal temperature under different running conditions were also captured well. The V2F turbulence model has been compared with a low-Reynolds-number k-ε model and a nonlinear quadratic k-ε model. The V2F model is found to provide the closest agreement with the data, though it still has room for improvement in predicting the boundary layer transition and turbulent heat transfer, especially on the suction side. The overall results are quite encouraging and indicate that conjugate heat transfer simulation with proper turbulence closure has the potential to become a viable tool in turbine heat transfer analysis and cooling design.

Conjugate Heat Transfer Analysis of Internally Cooled Turbine Blade

2012 ◽  
Author(s):  
Ilhan Gorgulu ◽  
Baris Gumusel ◽  
I. Sinan Akmandor
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Turbulence Model ◽  
Conjugate Heat Transfer ◽  
Turbulence Models ◽  
Heat Transfer Analysis ◽  
Internal Cooling ◽  
Turbine Blade Cooling ◽  
Internally Cooled ◽  
Rib Turbulators

There are different characters of air flow in a conventional gas turbine blade cooling channel. These flow characters; including high streamline curvature caused from 180 degree bends, sequential flow separations caused from rib turbulators and pin-fin structures are analyzed separately with available commercial software for different turbulence models and validated against reliable experimental data from open literature. Also coupled conjugate heat transfer analyses on NASA C3X vane, which has only radial holes through blade span for cooling, are conducted with the same turbulence models. The accuracy information gathered from all these analyses; each interested with a single character of air and coupled conjugate heat transfer are put together and applied to a conjugate numerical analysis of internally cooled (VKI) LS-89 turbine blade. Internal cooling scheme which is applied to (VKI) LS-89 turbine blade encompassed the aforementioned flow characters and analyses are performed under realistic conditions. Because of the high temperature values occurring at realistic conditions, thermal conductivity and specific heat capacity of air and metal (Inconel 718) are modeled as temperature dependent material properties instead of using constant values. Conducted research revealed that 4 eqn. V2-f turbulence model gives similar results compared to the 2 eqn. Realizable k-e, k-w SST turbulence models for 180 degree bend and rib turbulator cases. However, at NASA C3X vane analyses V2-f turbulence model results are far more accurate than other two turbulence models in the manner of heat transfer coefficient and surface temperature distribution.

Film Cooling Performances at Different Turbulence Intensities Using Conjugate Heat Transfer Analysis

2017 ◽  
Vol 872 ◽  
pp. 271-278
Author(s):  
Prasert Prapamonthon ◽  
Hua Zhao Xu ◽  
Jian Hua Wang
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Leading Edge ◽  
Suction Side ◽  
Heat Transfer Analysis ◽  
Internal Cooling ◽  
Large Area ◽  
Cooling Effectiveness ◽  
Flowing Fluid

This study presents a numerical investigation of cooling performances of a modified vane of the film-cooled vane reported by Timko (NASA CR-168289) at different mainstream turbulence intensities (Tus). A 3D conjugate heat transfer (CHT) analysis with SST k-ω turbulence model in FLUENT V.15 is used. Three different mechanisms in CHT analysis, i.e. fluid flow, heat convection between solid surfaces and flowing fluid in an external mainstream and internal cooling passages, and heat conduction within the vane structure, are simultaneously considered. Numerical results are conducted in terms of overall cooling effectiveness at Tu=3.3, 10, and 20%. Comparison between overall cooling effectiveness and film effectiveness under adiabatic assumption is discussed at the three Tus, also. The findings of this research indicate the following phenomena: 1) overall cooling effectiveness decreases with Tu, and this effect on the pressure side (PS) is stronger than that on the suction side (SS) in general. 2) By comparison with adiabatic film effectiveness, the level of overall cooling effectiveness in most regions is higher and more uniform than that of adiabatic film effectiveness for all three Tus. 3) In the leading edge (LE), when Tu increases, near the exits of film holes overall cooling effectiveness deteriorates, but adiabatic film effectiveness improves. Furthermore, a large area with relatively low overall cooling effectiveness is able to move with Tu in the LE region.

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