Numerical and Experimental Study on the Heat Transfer and Pressure Drop of Compact Cross-Corrugated Recuperators

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Zhou Guo-Yan ◽  
Tu Shan-Tung ◽  
Ma Hu-Gen
Keyword(s):  
Heat Transfer ◽  
Control Volume ◽  
Influence Factors ◽  
Sine Wave ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Clear Fluid ◽  
Transfer Factors ◽  
Periodic Cell ◽  
Dynamics Simulations

Recuperator is one of the key components in high temperature gas cooled reactors. Although cross-corrugated plates have been used to increase the thermal performance of the recuperators, the fundamental mechanisms of fluid flow and heat transfer are generally not clear. Fluid dynamics simulations and experiments are hence carried out to study the performance of the recuperators. A periodic cell is employed as the control volume. The flow field and heat transfer in sine-wave crossed-corrugated channels are investigated based on the Navier–Stokes and energy equations in the laminar flow regime between Re = 84 and 1168. The numerical results of the heat transfer factors and friction factors in different operating conditions show a fairly good agreement with the experimental measurements. The influence factors on the heat transfer and the hydraulic performance are also discussed in the paper. It is found that the heat transfer factor j and friction factor f decrease with the increase of the pitch-height ratio for a given Reynolds number.

A New Heat Transfer Correlation for Supercritical RP-3 Flowing in Vertical Tubes

2017 ◽  
Author(s):  
Longyun Wang ◽  
Zhi Tao ◽  
Jianqin Zhu ◽  
Haiwang Li ◽  
Zeyuan Cheng
Keyword(s):  
Heat Transfer ◽  
Influence Factors ◽  
Hydrocarbon Fuel ◽  
Operating Conditions ◽  
Major Influence ◽  
Absolute Deviation ◽  
New Correlation ◽  
Vertical Tubes ◽  
Correction Terms ◽  
Good Agreement

A new empirical correlation for upward flowing supercritical aviation kerosene RP-3 in the vertical tubes is proposed. In order to obtain the database, numerical simulation with a four-component surrogate model on RP-3 and LS low Reynolds turbulence model in vertical circular tube has been performed. Tubes of diameter 2mm to 10mm are studied and operating conditions cover pressure from 3MPa to 6MPa. Heat flux is 500KW/m2, mass flow rate is 700kg/(m2·s). The numerical results on wall temperature distribution under various conditions are compared with experimental data and a good agreement is achieved. The existing correlations are summarized and classified into three categories. Three representative correlations of each category are selected out to evaluate the applicability in heat transfer of supercritical RP-3. The result shows that correlations concluded from water and carbon-dioxide do not perform well in predicting heat transfer of hydrocarbon fuel. The mean absolute deviation of them is up to 20% and predict about 80% of the entire database within 30% error bands. So a new correlation which is applicable to different working conditions for supercritical RP-3 is put forward. Gnielinski type has been adapted as the basis of the new correlation for its higher accuracy. In consideration of major influence factors of supercritical heat transfer, correction terms of density and buoyancy effect are added in. The new correlation has a MAD of 9.26%, predicting 90.6% of the entire database within ±15% error bands. The comparisons validate the applicability of the new correlation.

scholarly journals A Comparison of Experimental and Computational Heat Transfer Results for a Leading Edge Impingement System

2018 ◽  
Vol 3 (4) ◽  
pp. 23
Author(s):  
Robert Pearce ◽  
Peter Ireland ◽  
Ed Dane ◽  
Janendra Telisinghe
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Turbine Blades ◽  
Leading Edge ◽  
Reynolds Numbers ◽  
High Heat ◽  
Navier Stokes ◽  
Spatially Resolved ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

Leading edge impingement systems are increasingly being used for high pressure turbine blades in gas turbine engines, in regions where very high heat loads are encountered. The flow structure in such systems can be very complex and high resolution experimental data is required for engine-realistic systems to enable code validation and optimal design. This paper presents spatially resolved heat transfer distributions for an engine-realistic impingement system for multiple different hole geometries, with jet Reynolds numbers in the range of 13,000–22,000. Following this, Reynolds-averaged Navier-Stokes computational fluid dynamics simulations are compared to the experimental data. The experimental results show variation in heat transfer distributions for different geometries, however average levels are primarily dependent on jet Reynolds number. The computational simulations match the shape of the distributions well however with a consistent over-prediction of around 10% in heat transfer levels.

Steady and Unsteady Modeling for Heat Transfer Predictions of High Pressure Turbine Blade Internal Cooling

2012 ◽  
Author(s):  
Rémy Fransen ◽  
Nicolas Gourdain ◽  
Laurent Y. M. Gicquel
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Cooling System ◽  
Transfer Problem ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Wall Region ◽  
Internal Cooling ◽  
Computational Domain ◽  
Complex Flow

This work focuses on numerical simulations of flows in blade internal cooling system. Large Eddy Simulation (LES) and Reynolds-Averaged Navier Stokes (RANS) approaches are compared in a typical blade cooling related problem. The case is a straight rib-roughened channel with high blockage ratio, computed and compared for both a periodic and full spatial domains. The configuration was measured at the Von Karman Institute (VKI) using Particle Image Velocimetry (PIV) in near gas turbine operating conditions. Results show that RANS models used fail to predict the full evolution of the flow within the channels where massive separation and large scale unsteady features are evidenced. In contrast LES succeeds in reproducing these complex flow motions and both mean and fluctuating components are clearly improved in the channels and in the near wall region. Periodic computations are gauged against the spatial computational domain and results on the heat transfer problem are addressed.

Pressure Drop Characteristics of Parallel-Plate Channel Flow With Porous Obstructions at Both Walls

2003 ◽  
Author(s):  
Marcelo J. S. de Lemos ◽  
Luzia A. Tofaneli
Keyword(s):  
Numerical Solutions ◽  
Control Volume ◽  
Computational Domain ◽  
Algebraic Equations ◽  
Clear Fluid ◽  
Simple Method ◽  
Periodic Cell ◽  
Porosity And Permeability ◽  
Volume Method ◽  
Turbulence Transport

In this work, numerical solutions are presented for turbulent flow in a channel containing fins made with porous material. The condition of spatially periodic cell is applied longitudinally along the channel. A macroscopic tow-equation turbulence model is employed in both the porous region and the clear fluid. The equations of momentum, mass continuity and turbulence transport equations are written for an elementary representative volume yielding a set of equations valid for the entire computational domain. These equations are discretized using the control volume method and the resulting systems of algebraic equations is relaxed with the SIMPLE method. Results are presented for the velocity field as a function of Reynolds number, porosity and permeability of the fins.

Turning Guide Vane Effect on Internal Cooling of Two-Passage Channel With Parallel Ribs

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Mandana S. Saravani ◽  
Ryoichi S. Amano ◽  
Nicholas J. DiPasquale ◽  
Joseph Wayne Halmo
Keyword(s):  
Heat Transfer ◽  
Guide Vane ◽  
Constant Heat Flux ◽  
Operating Conditions ◽  
Internal Cooling ◽  
Flux Boundary Condition ◽  
Flow And Heat Transfer ◽  
Computational Fluid Dynamics Simulations ◽  
Heat Flux Boundary Condition ◽  
Dynamics Simulations

Abstract The present work investigates the effects of various guide vane designs on the heat transfer enhancement of rotating U-duct configuration with parallel 45-deg ribs. The ribs were installed on the bottom wall of the channel, which has a constant heat flux boundary condition. The channel has a square cross section with a 5.08 cm hydraulic diameter. The first and second passes are 514 mm and 460 mm, respectively. The range of Reynolds number for turbulent flow is up to 35,000. The channel rotates at various speeds up to 600 rpm, which brings the maximum rotation number of 0.75. Several computational fluid dynamics simulations are carried out for this study to understand the effect of guide vanes on flow and heat transfer in serpentine channels under various operating conditions.

Investigation on the Internal Cooling of Two-Passage Channels With Parallel Ribs and Guide Vanes

2019 ◽  
Author(s):  
Ryoichi S. Amano ◽  
Mandana S. Saravani ◽  
Nicholas DiPasquale
Keyword(s):  
Heat Transfer ◽  
Guide Vane ◽  
Constant Heat Flux ◽  
Operating Conditions ◽  
Internal Cooling ◽  
Flux Boundary Condition ◽  
Guide Vanes ◽  
Flow And Heat Transfer ◽  
Speed Up ◽  
Dynamics Simulations

Abstract The present work investigates the effects of various guide vane designs on the heat transfer enhancement of rotating U-Duct configuration with parallel 45-deg ribs. The ribs were installed on the bottom wall of the channel which has a constant heat flux boundary condition. The channel has a square cross-section with a 5.08 cm (2 in) hydraulic diameter. The first and second passes are 514 mm and 460 mm, respectively. The range of Reynolds number for turbulent flow is up to 35,000. The channel rotates in various speed up to 600 rpm which brings the maximum rotation number of 0.75. Several computational fluid dynamics simulations are carried out for this study to understand the effect of guide vanes on flow and heat transfer in serpentine channels under various operating conditions.

Study of the Dynamic and Thermal Behaviors of an Air Flow in a T-Bifurcation

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Ali Riahi ◽  
Julien Pelle ◽  
Lilia Chouchene ◽  
Souad Harmand ◽  
Sadok Ben Jabrallah
Keyword(s):  
Heat Transfer ◽  
Stokes Equations ◽  
Initial Conditions ◽  
Research Work ◽  
Internal Surface ◽  
Numerical Approach ◽  
Navier Stokes ◽  
Flow Ratio ◽  
Sst Turbulence Model ◽  
Dynamics Simulations

This paper presents a numerical and experimental study of a turbulent flow of air in a T-bifurcation. This configuration corresponds to a stator containing radial vents oriented vertically to the rotor–stator air gap in electrical machines. Our analysis focuses on the local convective heat transfer over the internal surface of the vents under a turbulent mass flow rate. To model the cooling installation in this region, computational fluid dynamics simulations and an experiment using particle image velocimetry (PIV) are performed. The resulting flow generally produces recirculation zones in various channels. The effect of the flow ratio and diameter of the bifurcation on the dynamic and thermal behavior of the flow is also examined. In this study, we apply a numerical approach based on the k–ω shear stress transport (SST) turbulence model (using the commercial software, “comsolmultiphysics”) to numerically solve the Navier–Stokes equations and energy equation of the system under consideration. We describe the different hypotheses necessary to formulate the equations governing the problem, initial conditions, and boundary condition. The velocity in the bifurcation calculated using the simulation is compared with that obtained by the experiment and it reveals a good agreement. The effect of the branch diameter of the bifurcation and flow ratio on the heat transfer is specifically analyzed in this research work.

Heat Transfer Measurements and Predictions for a Modern, High-Pressure, Transonic Turbine, Including Endwalls

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
James A. Tallman ◽  
Charles W. Haldeman ◽  
Michael G. Dunn ◽  
Anil K. Tolpadi ◽  
Robert F. Bergholz
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Turbulence Modeling ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Test Facility ◽  
Navier Stokes ◽  
Local Measurements ◽  
Transonic Turbine ◽  
The Ohio State University

This paper presents both measurements and predictions of the hot-gas-side heat transfer to a modern, 112 stage high-pressure, transonic turbine. Comparisons of the predicted and measured heat transfer are presented for each airfoil at three locations, as well as on the various endwalls and rotor tip. The measurements were performed using the Ohio State University Gas Turbine Laboratory Test Facility (TTF). The research program utilized an uncooled turbine stage at a range of operating conditions representative of the engine: in terms of corrected speed, flow function, stage pressure ratio, and gas-to-metal temperature ratio. All three airfoils were heavily instrumented for both pressure and heat transfer measurements at multiple locations. A 3D, compressible, Reynolds-averaged Navier–Stokes computational fluid dynamics (CFD) solver with k-ω turbulence modeling was used for the CFD predictions. The entire 112 stage turbine was solved using a single computation, at two different Reynolds numbers. The CFD solutions were steady, with tangentially mass-averaged inlet/exit boundary condition profiles exchanged between adjacent airfoil-rows. Overall, the CFD heat transfer predictions compared very favorably with both the global operation of the turbine and with the local measurements of heat transfer. A discussion of the features of the turbine heat transfer distributions, and their association with the corresponding flow-physics, has been included.

Numerical Simulation for Thermal Design of a Gas Water Heater With Turbulent Combined Convection

2015 ◽  
Author(s):  
Ali Yari ◽  
Siamak Hosseinzadeh ◽  
Ali Akbar Golneshan ◽  
Ramin Ghasemiasl
Keyword(s):  
Heat Transfer ◽  
Control Volume ◽  
Geometric Parameters ◽  
Thermal Design ◽  
Navier Stokes ◽  
Total Efficiency ◽  
Water Heater ◽  
Hydrodynamic Behaviour ◽  
Turbulent Models ◽  
Energy Equations

This article investigates the effects of geometric parameters on a turbulent asymmetrical heat transfer in vertical channels with radiation and blowing from a wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier–Stokes and energy equations using a control volume finite element method. In this paper, commercial codes were used to solve the equations. The equations involved were numerically solved with three turbulent models including Spalart-Allmaras, R-N-G k-ε with ‘standard wall function’ wall nearby model, R-N-G k-ε with ‘enhanced wall treatment’ wall nearby model and ‘ray tracing’ radiation techniques. Turbulent flow with ‘low Reynolds Spalart-Allmaras turbulence model’ and radiation with ‘discrete transfer radiation method’ was modelled. The results were compared with experimental data and appropriate methods were selected for turbulent modelling. The problems of different Grashof number, Reynolds number, radiation parameters and Prandtl number were solved and the effects of geometric parameters on the fluid flow, radiation-convection-blowing heat transfer and the total efficiency were determined.

Combined Natural Convection and Volumetric Radiation in a Horizontal Annulus: Spectral and Finite Volume Predictions

1999 ◽  
Vol 121 (3) ◽  
pp. 610-615 ◽  
Author(s):  
D.-C. Kuo ◽  
J. C. Morales ◽  
K. S. Ball
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Stokes Equations ◽  
Control Volume ◽  
Navier Stokes ◽  
Differential Approximation ◽  
Navier Stokes Equations ◽  
Influence Matrix ◽  
Potential Benefits ◽  
The Mathematical Model

Combined natural convection and radiation in a two-dimensional horizontal annulus filled with a radiatively participating gray medium is studied numerically by using a control-volume-based finite difference method and a spectral collocation method coupled with an influence matrix technique. The mathematical model includes the continuity equation, the incompressible Navier-Stokes equations, the energy equation, and the radiative transfer equation (RTE), which is modeled using the P1 differential approximation. Computed results for two Rayleigh numbers, Ra = 104 and Ra = 105, for several combinations of the radiation-conduction parameter, NR, and the optical thickness, τ, are presented. The differences observed in the predicted flow structures and heat transfer characteristics are described. Furthermore, an unusual flow structure is studied in detail, and multiple solutions are found. Finally, the potential benefits of applying spectral methods to problems involving radiative heat transfer are demonstrated.

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