Frictional Heat Flux Research Articles

Method of mean-mass parameters for a three-dimensional boundary layer in a flow with vorticity

When a gas flows with hypersonic velocity over a slender blunt body, the bow shock induces large entropy gradients and vorticity near the wall in the disturbed flow region (in the high-entropy layer) [1]. The boundary layer on the body develops in an essentially inhomogeneous inviscid flow, so that it is necessary to take into account the difference between the values of the gas parameters on the outer edge of the boundary layer and their values on the wall in the inviscid flow. This vortex interaction is usually accompanied by a growth in the frictional stress and heat flux at the wall [2, 3]. In three-dimensional flows in which the spreading of the gas on the windward sections of the body causes the high-entropy layer to become narrower, the vortex interaction can be expected to be particularly important. The first investigations in this direction [4–6] studied the attachment lines of a three-dimensional boundary layer. The method proposed in the present paper for calculating the heat transfer generalizes the approach realized in [5] for the attachment lines and makes it possible to take into account this effect on the complete surface of a blunt body for three-dimensional laminar, transition, or turbulent flow regime in the boundary layer.

Free convection around a plate with temperature decreasing exponentially along the surface

Results of the numerical solution of a system describing nonselfsimilar natural convection in a laminar boundary layer near a vertical plate with exponentially decreasing temperature distribution are discussed. The nature of the development of the thermal and dynamical boundary layers as well as the friction stress and heat flux along the plate surface is given.

An Exact Solution of the Compressible-Flow Characteristics in Constant-Area Passages With Simultaneous Friction and Constant Heat Flux

An exact solution is presented for the flow of a compressible fluid in a constant-area passage in which wall friction is present and the total temperature of the fluid rises linearly with distance through the passage. For fluid properties that are invariant with temperature, this is specifically the case of constant heat flux. From this exact solution, an approximate simplified form is derived that should be applicable to predicting flow performance for most types of operation of constant-area heat exchangers.