Implications of boundary layer establishment

What is it about?

Short duration facilities are commonly used in heat transfer experiments due to the inexpensive operation and high temperature gradients, resulting in superior heat flux accuracy. However, a recent comparison between experimental data gathered in a reflected-shock tunnel and 2D steady RANS simulations concluded that the transient measurements over predicted the heat flux. This issue although previously identified in theoretical and analytical studies has not been experimentally assessed for actual turbine blowdown experiments. To ensure high fidelity in the transient experimental data one should carefully assess the boundary layer and overall flow establishment. The aim of the present paper is to study the transient development of both the aerodynamic and thermal boundary layers, with emphasis on their effect in the wall shear stress and heat transfer. This investigation will be focused on the boundary layer characterization during the startup phase of a subsonic blow down process

Featured Image

Why is it important?

When dealing with pulsating or sudden release flow discharges it is fundamental to understand the evolution of the thermal and momentum boundary layer during the entire process. Due to the behavior of the boundary layer there can appear severe overshoots of heat transfer and wall shear stress. In this paper we approach the analysis of the boundary layer development during a blowdown discharge based on CFD analysis.