ME Fundamentals Help

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Comments (2)

Quoc in Bremerton, Washington

108 months ago

I am studying Integral Relations for a Control Volume in Fluid Mechanics for the FE Exam. Is there a good way to remember the sign convection for heat flow rate (Q-dot), Mass Flow Rate (M-dot), and Shaft Work (W-dot). So far it is Positive if Heat flow goes into the system and shaft work is from the system; also, it is negative if mass flow rate is into the system. Is there a better to understand the sign convention or you just have to remember it?

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Jeremy in Singapore, Singapore

104 months ago

Well my uni. lecturer always stressed out this point long long ago, compressor is always deemed as "work in" into system denotes a "-ve" sign convention and for Shaft work (Turbine) as "+ve" "work out" of the system for Q dot.

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