Control Of Expansion Torque And Expansion Ratio Of NCu30 Double Tubesheet Heat Exchanger

The shell-and-tube heat exchanger consists of two major parts: the Tube side and the shell side.The double-tubesheet heat exchanger is a kind of shell-and-tube heat exchanger with special structure,this special structure can be used to prevent the mixing of materials in the Tube and Shell side,thus avoiding the occurrence of safety accidents in industrial production.The difficulty of manufacturing double tubesheet heat exchanger lies in the connection between heat exchanger tube and inner tubesheet.At present,strength expansion is the main form of connection between tubes and inner tubesheet in double tubesheet heat exchanger,however,it is necessary to determine the expansion parameters and main influencing factors through a series of expansion tests to ensure the strength and sealing of the expansion joint and the quality of the expansion joint,and to analyze and control them.In this thesis,a single-hole and a seven-hole expansion specimen are made for the strength expansion of NCu30 heat exchanger tube to 16 MnDR inner tube sheet.The expansion Torque is the main control parameter,and the expansion rate is the main test parameter,the reasonable expansion torque and expansion rate of NCu30 heat exchanger tube are obtained by the method of mechanical expansion,the parameter is successfully applied to engineering practice,and the stress distribution of NCu30 heat exchanger tube is obtained by the experimental stress analysis.Ф25×2mm NCu30 heat exchanger tube expansion test and anatomical inspection show that when the expansion rate of NCu30 heat exchanger tube is controlled at 6% ~8%,the tube head expansion can meet the expansion strength requirement,and the Tube pull-out can reach the peak value.Further analysis shows that the expansion rate increases with the expansion Torque,and the expansion torque has some effect on the expansion rate.The calculation of expansion ratio is relatively complicated,and the expansion torque is more accurate and suitable than the expansion ratio;when the reasonable expansion torque ofФ25×2mm NCu30 heat exchanger tube and δ35mm thick 16 MnDR tube sheet is 30N·M.the strength and tightness of the expansion joint can be guaranteed.In this thesis,the reasonable expansion control parameters and expansion test parameters of NCu30 heat exchanger tube and 16 MnDR inner tube sheet are obtained by mechanical expansion test.The research results can provide an important technical basis for the connection between heat exchanger tubes and inner tubesheet of double tubesheet heat exchanger,and guarantee the expansion strength and sealing performance of shell-and-tube heat exchanger and the quality of expansion.