Lecture 16 Notes - EGN 3353C Fluid Mechanics Lecture 16 Ex...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
EGN 3353C Fluid Mechanics Lou Cattafesta MAE Dept. University of Florida Lecture 16 Ex 5-11 Effect of Friction on Fluid Temperature and Head Loss Show that during steady and incompressible flow of a fluid in an adiabatic flow section ( a ) the temperature remains constant and there is no head loss when friction is ignored and ( b ) the temperature increases and some head loss occurs when frictional effects are considered. Discuss if it is possible for the fluid temperature to decrease during such flow. Sol . ± Since ρ = const (incompressible flow), then 2 1 ln v T c T s Δ= . + r*ln(ro1/ro2) <- This is zero, ro constant ± s Δ is caused by (1) heat transfer and (2) irreversibilities. Since the flow adiabatic, 0 Q = ± . s Δ is caused by irreversibilities (i.e., friction) ± 21 n e t i n L h uuq −− = () ( ) v gc T Tg =− (a) friction is 0 Æ 2 1 ln 0 v T sc T = Æ TT = Æ 0 L h = . When there is no heat transfer and no friction, the flow is isentropic, and temperature remains constant and there is no head loss. (b) friction is not 0 Æ 2 1 l 0 n v T T > Δ→ > = and 0 L h > . When there is no heat transfer but there is friction, some of the mechanical energy is converted to heat, causing temperature to rise and head loss.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
EGN 3353C Fluid Mechanics Lou Cattafesta MAE Dept. University of Florida Ex 5-12 Pumping power and frictional heating in a pump (caused by losses) The pump of a water distribution system is powered by a 15-kW electric motor whose efficiency is 90 percent. The water flow rate through the pump is 50 L/s. The diameters of the inlet and outlet pipes are the same, and the elevation difference across the pump is negligible. If the pressures at the inlet and outlet of the pump are measured to be 100 kPa and 300 kPa (absolute), respectively, determine ( a
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/17/2011 for the course EGN 3353C taught by Professor Lear during the Spring '07 term at University of Florida.

Page1 / 7

Lecture 16 Notes - EGN 3353C Fluid Mechanics Lecture 16 Ex...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online