conductivity of 400Wm1 K1 while this value was
about 0.25 m for tube with thermal conductivity of
16Wm1 K1. The slopes of tangent lines on the temperature
curves of gas flow were 1.41 and 1.80 K mm1 for tube
thermal conductivities of 400 and 16Wm1 K1, respectively.
This means that axial positioning error dominates
in temperature measurements where the temperature
gradient is significant along the tube. Therefore, the tube
wall thermal conductivity cannot predict the value of