Numerical method for prediction of material's properties effect on temperature difference in the gap of contact surface during conduction heat transfer

Gaps are always present in the contact surfaces of two solid material. Air trapped in the gaps inhibit heat transfer and causes the contact resistance. Temperature difference between the contact surfaces is very important in many practical applications, however, it is difficult to be measured. In this study, the temperature difference in the gap is estimated by numerical methods of one-dimensional conduction heat transfer without taking into account the surface roughness, elasticity of the material, and the contact pressure. The numerical methods is used to estimate the gap temperature difference in the contact surface of thermoplastic types of polypropylene material, limestone, steel, and copper. The results show that the temperature difference in the gap depends on the properties of the contact material and the air, such as thermal conductivity, density, and specific heat. The larger the thermal conductivity of solid material the lower the temperature difference in the gap and the shorter the transient time for the gap temperature difference to reach its maximum. Once it becomes maximum, the temperature difference in the gap fluctuated periodically with the amplitude becoming increasingly larger. The greaterthe value of thermal conductivity the higher the fluctuation frequency of the temperature difference in the gap and the temperature difference tends to be negative at very high thermal conductivity.