The compatibility of the heat pipe means that the heat pipe does not undergo significant chemical reaction or physical change with the casing within the expected design life, or there is a change but not enough to affect the working performance of the heat pipe. Compatibility is of great importance in the application of heat pipes. Only long-term compatible heat pipes can guarantee stable heat transfer performance, long-term working life and the possibility of industrial application. The carbon steel-water heat pipe is a chemical treatment method that effectively solves the chemical reaction problem between carbon steel and water, so that the carbon steel-water heat pipe is a high-performance, long-life, low-cost heat pipe that can be industrialized. Scale promotion.
There are many factors affecting the life of heat pipes. In summary, the main forms of inefficiency in effect tube are as follows: non-condensable gas: deterioration of thermal properties of working liquid: corrosion and dissolution of shell material.
(1) Producing non-condensable gas The non-condensable gas is generated due to chemical reaction or electrochemical reaction between the working liquid and the tube material. When the heat pipe is working, the gas is swept by the steam stream to the condensing section to form a gas plug. Thus, the effective condensation area is reduced, the thermal resistance is increased, the heat transfer performance is deteriorated, and the heat transfer capability is lowered or even failed.
(2) Deterioration of working fluid properties The organic working medium will gradually decompose at a certain temperature, mainly due to the unstable nature of the organic working fluid or chemical reaction with the shell material, so that the working medium changes its physical properties, such as Organic working fluids such as toluene, alkane, and hydrocarbons are prone to such incompatibility.
(3) Corrosion, dissolution and working fluid of the shell material continuously flow in the shell, and there are factors such as temperature difference and impurities, which cause the shell material to dissolve and corrode, and the flow resistance increases, which reduces the heat transfer performance of the heat pipe. When the shell is corroded, the strength is reduced, and even the corrosion and perforation of the shell is caused, so that the heat pipe is completely ineffective. This type of phenomenon often occurs in alkali metal high temperature heat pipes.