What happens when flow separates?

Flow separation or boundary layer separation is the detachment of a boundary layer from a surface into a wake. In aerodynamics, flow separation results in reduced lift and increased pressure drag, caused by the pressure differential between the front and rear surfaces of the object.

How does the flow rate affect the convective heat transfer?

The effect of the mass flow rate at constant velocity on the convective heat transfer coefficient of an incompressible fluid in a turbulent flow regime is presented with the help of dimensional analysis. Doubling the mass flow rate will result in a 92\% increase in the heat transfer coefficient.

Why is flow separation important?

Flow separation is perhaps the most important unsolved phenomenon of fluid mechanics which causes energy loss and deviation of stream lines. A summary of flow separation is presented in order to understand the basic problem, the present state of knowledge and to indicate future development.

Why is turbulent flow better for heat transfer?

Under turbulent flow conditions, the increase in heat transfer rate is more significant than that under laminar flow conditions. This is due to the increase in the Reynolds number of the flowing fluid in turbulent flow. The turbulent effects become a dominant factor over secondary flow at higher Reynolds number.

Does heat transfer coefficient depend on flow rate?

The fluid motion enhances heat transfer (the higher the velocity the higher the heat transfer rate). The convective heat transfer coefficient h strongly depends on the fluid properties and roughness of the solid surface, and the type of the fluid flow (laminar or turbulent).

What is the relationship between flow rate and temperature?

The flow rate is inversely proportional to the temperature difference.

What factors affect the heat transfer rate?

kcan be calculated from the following equation: Here, a1 and a2 are the heat transfer coefficients on each side of the material in the heat exchanger. They give the quantity of energy transferred from a liquid or gas to or from unit area of a fixed mate-rial and per degree temperature difference.

What factors affect heat transfer coefficient?

Heat transfer coefficient depends on both the thermal properties of a medium, the hydrodynamic characteristics of its flow, and the hydrodynamic and thermal boundary conditions.

Why does flow separation reduce lift?

Flow separation causes turbulence which destroys lift and generates increased drag. Wing lift depends on smooth airflow over and under the wing. Anything that disturbs that smooth air flow reduces lift, mainly due to the turbulence created.