Device and method for detecting thermal expansion coefficient of fluorocarbon insulation cooling liquid

The invention discloses a device and a method for detecting the thermal expansion coefficient of fluorocarbon insulation cooling liquid. The device comprises a constant-temperature box, a sealing pipe, a sealing plug, a capillary tube, a temperature probe and a condensation assembly, fluorocarbon insulation cooling liquid is contained in the sealing pipe, and the temperature probe penetrates through the sealing plug to be arranged in a cavity of the sealing pipe so as to monitor the real-time temperature of the fluorocarbon insulation cooling liquid; the bottom of the capillary tube is inserted into the sealing plug, the top of the capillary tube is in sealed connection with the condensation assembly, and the condensation assembly is used for condensing the vaporized fluorocarbon insulating cooling liquid and enabling the liquid fluorocarbon insulating cooling liquid to flow back to the capillary tube; the detection method comprises the following steps: adjusting the temperature of the thermostat, recording t