Converting mass volume to mass flow

[Rog50]

Hello forum. I’m new to Eng-Tips, so I hope I got this on the right board.
I’m working with a Cat 3516 gas engine on a low btu application. I need to spec a fuel metering valve to control mass flow to the engine and maintain my Air/Fuel ratio for emissions. I know the mass volume of gas (cfm) the engine needs based on the btu rating of our gas along with its SG. The metering valve will compensate for temp and pressure but is rated in Kg/hr. What I’m looking for is a formula to convert my mass volume to mass flow i.e: CFM to Kg/hr to determine the correct valve size.
Thanks

 

[Pumpsonly]

First of all,please look at the title of your thread...it does not make sense ..Mass volume to mass flow"...

You can down load the conversion from the below link..

http://www.katmarsoftware.com/uconflow.htm

 

[zdas04]

The engine]/b] actually needs mass. It is probably rated in SCFM (not CFM) which is standard cubic feet per minute. SCFM (like mass flow rate in a unit like kg/hr) is not pressure dependent like ACFM is. To get from volume flow rate to mass flow rate, multiply volume flow rate times the density of the gas at std temp and press. Density=(P*SG)/(R(air)*T) (you can disregard compressibility for std conditions, and P & T must be in absolute units).

If it is rated at ACFM then you need to get density at flowing conditions (compressibility may or may not be material). and multiply that density times the ACFM number. This is less common in equipment rating.

David