An experimental investigation on forced convection heat transfer performance in micro tubes by the method of liquid crystal thermography

This study proposed a non-contacted liquid crystal thermography (LCT) method for micro tube surface temperature measurement. It avoids the thermal shunt error caused while using the direct contact thermocouples. Two stainless steel tubes with inside diameter of 123 μm and 962 μm were tested. The test results agree very well with those predicted by the conventional correlations. It successfully extends the validity of conventional single-phase heat transfer correlations to the tube with inside diameter of 123 μm. This method can be further applied for measuring smaller tube surface temperature that the thermal shunt may be more significant by using direct contact temperature measurements methods.