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How to convert PPMw (by weight) to PPMv(Volume) for H2S & moisture(H2O) in gas mixture?
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Submitted Chris Haslego, Nov 21 2011 11:21 AM | Last updated Nov 21 2011 01:29 PM

Category:	Fluid Dynamics
Question:	How can one estimate how the friction factor changes in heat exchanger tubes with a change in temperature?
Keywords:	v1i1,heat,exchanger,tube,friction,factor,change,changes,temperature
Answer:	Seider and Tate recommended the following for determine friction factors inside heat exchanger tubes with varying temperatures:First, determine the average, bulk mean temperature in the processing line. For example if the fluid enters the line at 300 ??C and leaves at 280 ??C, use 290 ??C to determine the physical properties and friction factors.As for corrections:Laminar FlowIf the liquid is cooling, the friction factor obtained from the mean temperature and bulk properties is divided by (bulk viscosity/wall viscosity)^0.23 and for heating, it's divided by (bulk viscosity/wall viscosity)^0.38. Here, the bulk and wall viscosity are determined at the mean temperature over the length of the line.Turbulent FlowIf the liquid is cooling, the friction factor obtained from the mean temperature and bulk properties is divided by (bulk viscosity/wall viscosity)^0.11 and for heating, it's divided by (bulk viscosity/wall viscosity)^0.17. Here, the bulk and wall viscosity are determined at the mean temperature over the length of the line.Source: Perry's Chemical Engineers' Handbook