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Hello All, I would like to know how to calculate the boundary layer thickness for a flow through pipes (internal flow). I can find a lot of information of boundary layer thickness for flow over flat plate, but not for internal flow. Any help is appreciated Thanks

Thank you for your inputs. If I am interested in a first order approximation of the pressure drop across the rect cylinder. Also I dont think the Re would go beyond 5x10^4. In that case would the above equation be sufficient. Also I would like to ask you if there is a way to convert Cd to...

Hi, I am interested in calculating the pressure drop across rectangular cylinder. I know the coefficient of drag of the cylinder from the Cd vs Re plot and the drag force across the cylinder is given by Fd = Cd * 0.5 * rho * V^2 * frontal area. How do i calculate the pressure drop from the...

Thank you, ione. Let I shall read through the attachment and get back to you in case I have further questions.

Hi, I have a question in calculating Nusselt and friction factor for flow in pipes. The flow in a pipe could be hydrodynamically developing, hydrodynamically fully developed, thermally developing and simultaneously developing and these four scenarios can occur for laminar and turbulent flow...

Thank you everyone for your inputs and clarifying my question.

Correct me if I am wrong. Pdownstream = 14.7 psia Critical pressure ratio for air = 0.528 Pupstream = 14.7 / 0.528 = 27.8 psia Hence the flow must be choked if the upstream is at 27.8 psia and the outlet is at 14.7 psia. However increasing upstream pressure will increase the mass flow rate...

Thank you everyone for your response. I got a air valve sized up by a sales guy for the following conditions. 114.7 psia upsteam 14.7 psia downstream The Mach number through the sized up valve is 0.85. Pressure ratio: 114.7/14.7 = 7.8 Choked flow occurs when mach no is 1. But in this case...

Thank you for your replies. I have air coming in at 200 psi and the outlet pressure is 100 psi. The velocity through the valve is not sonic. Will the valve choke? I do realise that P* is 0.528 and Po/Pi = 0.5. Kindly clarify

Hi, I would like to know if choked flow can occur in a valve even if the velocity of air passing through the valve has not reached Mach 1. Also how will I determine is the flow is choked or not, given I know the upstream and downstream pressures. Thank you

I think I should have put the question in better words. I am not looking for the laws of thermodynamics. What i was exactly interested was how the numbers in a thermodynamic property tables (for fluids such as steam, nitrogen, R134a etc) are calculated. Are they interpolated values based on...

@Foure and MortenA: Thanks!

@ Twoballcane: Not to be rude..what are u getting at? All I am trying to figure out is how are the properties say in a saturated steam table obtained for a given Tsat or Psat?

@zdas04 - I do use refprop to get the properties. But I was curious as to how the properties were being calculated. The property calculations in refprop are based on complex algorithms. I was wondering if someone could direct me as to what equations are being used.

Hi, I would like to know what equations are used to calculate thermodynamic properties like enthalpy, Cp, entropy at a given temperature and pressure. I know i can use standard tables for these values, but I am curious as to how these are calculated. I am looking for equations in which i can...