The traditional analysis method is not practical in the power prediction and parameter optimization analysis of low temperature differential Stirling engine. In order to predict the output power of low temperature differential Stirling engine quickly, this paper studied the application of the second order Simple model in the thermodynamic cycle analysis of low temperature differential Stirling engine. It described the simplified structural model of low temperature differential Stirling engine and the temperature characteristics of internal working medium. Based on Simple model, this study derived the actual heat transfer equation of non-ideal heat exchanger in low-temperature differential Stirling engine, and analyzed the heat return loss, pumping loss and actual heat transfer of heat exchanger. The variation of the temperature, pressure and energy of the working medium in the low-temperature differential Stirling engine system with the crank Angle was illustrated by examples, and the theoretical output power of the low-temperature differential Stirling engine was analyzed. The actual output power of low temperature differential Stirling engine at different heating temperatures was compared with the calculated power of Simple model. The comparison results show that the error between the output power calculated by the Simple model and the actual output power is small, indicating that the Simple model is in good agreement with the actual cycle of the low-temperature differential Stirling engine. In order to study the influence of regenerator on engine performance of low temperature difference Stirling engine, the paper optimized the structure of regenerator of low temperature difference Stirling engine. The output power of the regenerator after optimization was compared with that before optimization. The comparison results show that after optimizing the regenerator, the actual output power of the low-temperature differential Stirling engine and the calculated power of the Simple model are both increased by 20%. It is shown that optimizing the structure of regenerator is an effective method to improve the performance of low temperature differential Stirling engine.

In-mold hot-pressing is a common drying method in the production of pulp moulded tableware. The wet paper mold embryo obtained after moulding is heated under the condition of extrusion and vacuum. Heating plate is the heat source of hot-pressing machine, and the temperature uniformity of its working surface affects the drying quality of products. Aiming at the temperature non-uniformity of the heating plate in the process of pulp molding hot pressing, this paper proposed an optimization method which combined simulation and orthogonal experiment. Firstly, the working process of heating plate was analyzed and the heat transfer model of heating plate was established. Then, based on Fluent, the temperature field was simulated numerically. According to the results of temperature field distribution, the high-temperature area and low-temperature area in the oil circuit structure were staggered as far as possible, and four new labyrinth oil circuit structures were designed. Finally, an orthogonal test with 4 factors and 4 levels was designed based on the structure of oil circuit, the plane height of oil circuit, the thickness of heating plate and the section diameter of oil circuit, and the range analysis and variance analysis were carried out. The results show that during the actual drying process, the maximum temperature and minimum temperature of the working surface are 224.47 ℃ and 209.92 ℃, respectively, and the temperature range is as high as 14.55 ℃ and the temperature standard deviation is 3.01 ℃. The thickness of heating plate and the diameter of oil passage have a significant influence on the temperature difference, and the structure of oil passage has a significant influence on the temperature standard deviation. Based on the above analysis, the structure of heating plate was improved. Compared with the original design, the temperature range of the working surface of heating plate has been reduced to 7.27 ℃ and the temperature standard deviation has been reduced to 1.09 ℃ , which ensures the uniformity of temperature of heating plate and improves the quality of pulp molded products.

In order to study the response characteristics of the scissor-type deployable element under vibration conditions, the study used the ship rust removal device as the vibration source and firstly established the mechanical model of the scissor-type deployable element. And the reliability of the element members under extreme conditions was studied. Then it used numerical modal analysis method and dynamic stress test analysis method under random vibration to study the random excitation problem and response of the scissor expandable unit under vibration conditions. It proposed a method to eliminate the second-order transverse bending vibration and excitation resonance of the scissor expandable unit and carried out dynamic stress simulation for each structural optimization scheme. The results show that the second-order modal vibration (306.15 Hz) of the scissor-type deployable unit and the random excitation resonance generated by rust removal are the main reasons for the vibration fatigue of the scissor-type deployable unit. The dynamic stress level of the unit can be reduced most significantly by increasing the thickness of the upper worktable from 10 mm to 14 mm, reducing the rigidity of the worktable from 20 GPa to 19.5 GPa, and adding a connecting shaft between the two connecting rods. The research results can provide a theoretical basis for the stable and reliable operation of the scissor deployable unit in engineering applications.