Theoretical Study On Output Torque Of Single Screw Expander And Analysis Of Performance Evaluation Parameters

Single screw expander as a new type of expander has good stability. At present, the research of single screw expander technology is still in the stage of development. In this paper, theoretical analysis of single screw expander performance has been studied, with single screw expander used in medium temperature industrial waste heat recovery system as the background. In this paper, the corresponding theoretical research on output torque of single screw expander has been done based on calculation for basic designed parameters of single screw expander. Preliminary analysis on the evaluation index of single screw expander by c is practical and universal.The main research contents are as follows:Firstly, the basic structure of single screw expander has been analyzed. Basic designed parameters of single screw expander have been introduced briefly, which provides a thorough grounding in theory and practice for the follow-up study. Volumetric element and pressure of single screw by analytic method was calculated.Secondly, curves of variation of volumetric element and pressure with screw rotational angle have been drawn applying MATLAB software. Inverse envelope works of single screw expander and the irreversible loss of actual process have been introduced simply, which provides a thorough grounding in study on the evaluation index of single screw expander.Thirdly, based on the basic structure of single screw expander, output torque of single screw expander has been calculated. Based on calculation on volumetric element and pressure of single screw, variation of torque with the screw rotational angles has been shown by analytic method. To single screw channel, the torque has a trend, which is rising and then descending. Besides the time to get the minimum value is when the air admission has begun in the single screw expander. The time to get the maximum value is when the expansion has happened. In the expansion, variation of torque is a periodic change and the cycle is 60°. variation of torque with the screw rotational angles with different single screw diameters is approximately the curve of sine.Fourthly, it is the first time to apply the new concept heat, internal energy entransy, for analysis on the thermal conversion. Compared the difference between inlet entransy minus outlet entransy to adiabatic efficiency, the two performance evaluation indexes are consistency. The theory of internal energy entransy is suitable for evaluating irreversibility in the expansion process.Finally, the physically significant of the internal energy entransy theory has been discussed. The internal energy entransy theory explores both the physical properties of working fluids and description of irreversibility in the expansion process. The internal energy entransy theory has a bright future in the thermal conversion.