Fluid Friction, Velocity Head, Flow Induction

Fluid Friction, Velocity Head, Flow Induction 

Fluid friction is covered by information on pressure losses in pipes, ducts, orifices, valves, and fittings in pt 5 of reference 51. 

If a gas or air current passes along a furnace wall or load surfaces, it is retarded by both viscosity and turbulence. The retardation due to turbulence grows with the roughness of the surface of the wall. By the law of conservation of momentum, flow deceleration causes a rise in pressure. 

In passing through tall ducts or tall apparatus, hot gases cool, contract in volume, and move more slowly. This is equivalent to a gradual enlargement of the stream cross 

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Temperature uniformity involves improvement by movement of radiating triatomic gases as well as convection poc. (See also chap. 5 of reference 51.) Concepts of this chapter will be facilitated by the following review of the laws of gas movement concerning buoyancy, velocity head, fluid friction between gases and solids, and flow induction. 

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