We have an 8" turbine meter measuring natural gas. Because the meter was calibrated at a temperature of 60 deg F and will be operated at 180 deg F, a question has been raised about the need to correct the meter factor for temperature effects.
It is standard practice to correct for thermal expansion of orifice and venturi type meters. It has been contended that thermal expansion will also change the "meter factor" of turbine meters from the value determined during calibration. This contention is based on three items.
1) The speed of the turbine blades is proportional to the average velocity of the flowing gas..
2) At the same gas velocity there will be more volume flow, because the flow area increases proportionately as the meter expands.
3) At the same gas velocity, and thus the same blade velocity, the angular velocity (RPM) of the meter will decrease as the meter expands.
Request
Is there any code, or published data and theory that refutes, acknowledges or confirms this contention?
Any information would be helpful.
It is standard practice to correct for thermal expansion of orifice and venturi type meters. It has been contended that thermal expansion will also change the "meter factor" of turbine meters from the value determined during calibration. This contention is based on three items.
1) The speed of the turbine blades is proportional to the average velocity of the flowing gas..
2) At the same gas velocity there will be more volume flow, because the flow area increases proportionately as the meter expands.
3) At the same gas velocity, and thus the same blade velocity, the angular velocity (RPM) of the meter will decrease as the meter expands.
Request
Is there any code, or published data and theory that refutes, acknowledges or confirms this contention?
Any information would be helpful.
