Rayleigh Flow

Rayleigh flow is model describing a frictionless flow with heat transfer through a pipe of constant cross sectional area. In practice Rayleigh flow isn't a really good model for the real situation. Yet, Rayleigh flow is practical and useful concept in a obtaining trends and limits such as the density and pressure change due to external cooling or heating. As opposed to the two previous models, the heat transfer can be in two directions not like the friction (there is no negative friction). This fact creates a situation different as compare to the previous two models. This model can be applied to cases where the heat transfer is significant and the friction can be ignored.

Figure 10.1: The control volume of Rayleigh Flow