Thermal mass flowmeter require temperature compensation during gas flow measurement ?
Yes, thermal mass flow requires temperature compensation. This is not the same as temperature correction, as you would see with a multivariable transmitter or external flow technologies, such as differential pressure, in order to obtain Nm3/h, SCFM, SCFH, etc.
Thermal manufacturers understand that gas properties that effect heat transfer vary with temperature. The process temperature is already being measured (by an RTD) and is accounted for in the calculation.