Comparing Advanced RANS Models to LES and Experiments in Ribbed Passage Heat Transfer Analysis
- Due No due date
- Points 0
Background
The introduction of artificial surface roughness in form of ribs for heat transfer enhancement is found in numerous engineering applications, e.g., gas turbines and heat exchangers. Such turbulence promoters disturb the flow and thus enhance convective heat transfer. There is a growing trend to use higher turbine inlet temperature in order to improve the performance of a modern gas turbine engine. The components of a gas turbine engine, especially the first moving stage blades are exposed to the higher turbine inlet gas temperature, which are far beyond the allowable metal temperatures. Accordingly, cooling techniques have been employed in order to maintain acceptable airfoil temperature and safety standards for the blade life. Figure 1 shows several techniques to cool a modern gas turbine blade. The blade consists of cooling passages lined with rib turbulators, which is the core of the present project. The penalty associated with such roughening is an increase in pressure loss. Despite numerous studies on heat transfer, turbulence and turbulent boundary layer in rough surface problems, the detailed physics of these flow problems are still a topic of research.
Aim
In the past few decades there have been several experimental and numerical studies of the rib-roughened surfaces. However, the most widespread techniques adopted were based on solution of the Reynolds-Averaged Navier-Stokes (RANS) equations, where the choice of turbulence model plays a critical role in determining the accuracy of the simulations. This project aims to carry out detailed flow and heat transfer measurements and evaluate the performance of few advanced RANS models against a Large Eddy Simulation and experimental results for a rib-roughened channel flow using OpenFOAM.
Figure 1. (a) sketch of an internally cooled turbine airfoil, (b) rectangular channel with a pair of opposite ribbed walls, (c) stramwise velocity and temperature variations through ribbed channel.
The project includes
It involves creation of simulation geometries for 2D/3D ribbed channels (only 2 or 3 units of roughness). You will investigate simulations of the flow and heat transfer in a 2D/3D rib-roughened passage using a number of advanced RANS turbulence models including Eddy-Viscosity Models (EVM) and a Reynolds Stress Model (RSM). Large Eddy Simulation (LES) will also be conducted and results will be compared against experimental measurements. In addition, the effects of rib thermal boundary condition on heat transfer will also be investigated. All computations are to be undertaken using the open source CFD code OpenFOAM.
Contact and more information
For more information, please contact Himani Garg, Assistant Professor at the Department of Energy Sciences: himani.garg@energy.lth.se.
References
- A. V. Baruskov, V. V. Terekhov and V. I. Terekov. Numerical simulation of a separated flow in a ribbed channel by the RANS and LES methods. J. Phys., 2039:pp. 012003, 2021.
- J. Ahn, H. Choi, and J. S. Lee. Large eddy simulation of flow and heat transfer in a rotating ribbed channel, Int. J. Heat Mass Transf., Vol. 50, pp. 4937-4947, 2007.
- Garg, Himani, Lei Wang, and Christer Fureby. Large-eddy simulations of separated flow and heat transfer in a ribbed channel. ICHMT Digital Library Online. Begel House Inc., 2023.