Saturday, May 16, 2015

Excel calculator for LMTD

LMTD, Log mean temperature difference is the temperature driving force for heat transfer in flow systems. When you are calculating heat transfer by overall heat transfer coefficient (U), you should not simply multiply temperature difference of hot stream or cold stream. Multiplying this temperature difference doesn't account the overall driving force.

Tuesday, May 12, 2015

Pressure drop in pipe lines and fittings. Part-2

Pressure drop due to valves and fittings

In the earlier post, tutorial goes around pressure drop in pipe lines. Pressure drop arises due to skin friction and form friction. Non separated boundary layers cause skin friction whereas separated boundary layers cause form friction. In plain pipe pressure drop is due to skin friction. But in a pipe line with valves and fittings pressure drop is  mainly due to form friction. the pipe lines may be connected to equipment and again pressure drop will be there in that equipment. This tutorial is restricted to pressure drop in valves and fittings only.