Numerical Study of Leading-Edge Heat Transfer Under Free-Stream Turbulence
Abstract
The effect of incoming organized disturbance and free-stream turbulence on leading-edge heat transfer is investigated numerically. An optimum length scale is found to give the maximum heat transfer enhancement for the organized disturbance case. Beyond this optimum value, the enhancement decreases with the increase of length scale. For the free-steam turbulence case, large eddy simulation with dynamic SGS model is performed at Reynolds number Re(D) = 10(exp 4) based on upstream velocity u(infinity) and the leading edge diameter of curvature D. The free-stream turbulence is specified as homogeneous, isotropic turbulence with intensity U'(rm8)/U(infinity) = 0.08 and integral length scale L/D = 0.1. Three different regions characterize the interaction of turbulence impinging on the leading edge. For the conditions of the simulations a turbulent beat transfer enhancement of 11% is obtained, which is in fair agreement with the experimental data. The level of heat transfer enhancement is modest because of the Reynolds number is low. However, our results show that in the region very close to the leading edge, the energetic turbulence length scale decreases to the order of 2-3 times the local boundary layer thickness, so a high grid resolution is needed for accurate prediction of heat transfer using large eddy simulation. This is a challenge for future investigations where simulations at higher Reynolds numbers and transonic flow conditions are planned. Our results motivate a hybrid simulation strategy where the turbulence outside and away from a blade surface is captured using LES techniques while a finer DNS-like grid is embedded within the near-wall region to resolve the smaller eddies responsible for near-wall effects. Such a methodology is being developed in an extension of the work supported under this grant.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2000
- Accession Number
- ADA388149
Entities
People
- Sanjiva K. Lele
- Zhongmin Xiong
Organizations
- Stanford University