Conjugate heat transfer

Conjugate Heat Transfer

An essential element of an adequate HP turbine design  is to be able to predict the blade metal temperatures. This involves convection heat transfer in the fluid part and conduction heat transfer in the solid part. The coupled convection-conduction conjugate heat transfer (CHT) modeling is important not only to blade heat transfer, but also to aerothermal performance prediction in general.  A fluid-only solution can become untenable due to the uncertain boundary condition for the energy equation when surface temperature is unknown. 

Development of CHT has been so far largely confined to steady flows. The key challenge is the time scale disparity.  In a recent work (He and Oldfield, 2011), a new approach to CHT for periodic unsteady flows is proposed. To realign the greatly mismatched time scales, a hybrid approach of coupling between time-domain fluid solution and frequency-domain solid conduction is adopted. A novel harmonic transfer function is introduced, leading to an efficient and consistent new semi-analytical framework for the wall boundary condition of  unsteady energy equation under  periodic or even non-periodic (e.g. turbulence) disturbances with LES  (He, 2013).

 

References:

-L. He and M.L.G, Oldfield, “Unsteady Conjugate Heat transfer Modelling”,  ASME Journal of Turbomachinery, Vol.133. No.3, 2011.

-L. He,  “Fourier Spectral Method for Multi-scale Aerothermal Analysis”,  International Journal of Computational Fluid Dynamics, Vol.27, No2, 2013, pp118-129.