Experimental Investigation on Thermal Contact Resistance of Interface Material of Piston With Composite Insulation Structure

The composite thermal insulation piston is a new type of piston for high power density diesel engine piston. Its structure is composed of a variety of materials, and the thermal contact resistance between the materials will affect the thermal insulation effect of the piston. Based on the steady-state heat flow method, an experimental device for measuring thermal contact resistance is developed. The interface thermal contact resistance between titanium alloy and heat-resistant steel, aluminum alloy and heat-resistant steel is measured. Further, the error of the test is analyzed. The maximum error of the interface thermal contact resistance is 5.81%. The influence of pressure and temperature on the interface thermal contact resistance of material under piston working condition is studied. The results show that the thermal contact resistance decreases with temperature increasing under the same pressure. Under the condition of low interfacial pressure condition, the change of temperature has obvious influence on the thermal contact resistance. At the same temperature, the greater the pressure at the interface, the smaller the contact thermal resistance. However, at different temperature stages, the decreasing range of contact thermal resistance is different. Under the same load and temperature conditions, the thermal contact resistance of the combination of titanium alloy and heat-resistant steel is larger than that of the combination of aluminum alloy and heat-resistant steel. Under the same load and temperature conditions, the interface thermal resistance of heat-resistant steel and aluminum alloy is smaller than that of titanium alloy and heat-resistant steel.