The Principle And Performance Study Of Shape Memory Alloy-piezoelectric Composite Thermal Power Generation

The waste heat generated by energy consumption in daily production and life is discharged in the form of waste hot gas and waste hot water.The emission forms are complicated and can not be used in large scale and effectively.Not only a large amount of energy is wasted,but also the environment is polluted.It is not coordinated with the current social development of low carbon environmental protection and energy saving and consumption reduction,and it is urgent to be changed.Nowadays,the research on the power generation based on smart materials such as piezoelectric,electrostatic,shape memory alloy and other intelligent materials is widely carried out,forming a variety of secondary energy reuse technologies and methods,showing a flourishing development situation.These days,there are not many cases that combine two or more than two kinds of smart materials for energy conversion.Combined with the National Natural Science Foundation,the research on the technology and methods of the composite thermal power generation technology and method of shape memory alloy?project number:51707081?,a thermoelectric conversion device which combines the shape memory alloy with the piezoelectric material is proposed.Combining the advantages of two kinds of intelligent materials,the heat energy is transformed into the mechanical energy by the shape memory alloy,and the piezoelectric vibrator is deformed or vibrated by mechanical energy,and then generate electricity.This paper focuses on their basic theories in system structure,structure design,energy conversion,collection and storage of electric energy and so on.It provides a new idea or new method for small residual heat power generation technology.The specific research contents of this paper are as follows:1.Design the general scheme of thermoelectric conversion device combined with shape memory alloy and piezoelectric material,discuss its working principle,and divide the thermoelectric conversion device into two parts:the mechanical structure part and the energy acquisition circuit.According to the characteristics of shape memory alloy and piezoelectric material,a thermoelectric conversion device is designed to fix the shape memory alloy wire on the two ends of the piezoelectric vibrator.According to the characteristics of piezoelectric power generation,the energy acquisition circuit combined with full bridge rectifier circuit and capacitor is adopted.2.The characteristics of SMA are analyzed.According to the constitutive equation,the mechanical properties of SMA at different temperatures are obtained.The deformation response speed of the shape memory alloy was measured by the experimental method,and the feasibility of the piezoelectric cantilever beam driven by shape memory alloy wire was discussed according to the response rate of the heat deformation.3.According to the deformation characteristics of piezoelectric cantilever,a theoretical model of piezoelectric cantilever generation under different loads is established.According to the deformation characteristics of SMA under different temperatures,the theoretical generation of piezoelectric cantilever is obtained.4.The three-dimensional model of piezoelectric cantilever beam is established,and the piezoelectric vibrator is simulated according to the fixed mode,load type and load size of the actual cantilever beam,and the generating capacity is obtained when the piezoelectric cantilever beam produces deformation.5.The prototype of thermoelectric conversion device is made,and the power generation situation of thermoelectric conversion device during heating is obtained through experiments.Using the device,the energy acquisition circuit is used to charge the storage elements,and the relationship between the charge times and the storage capacity of the storage elements is observed.According to the thermoelectric conversion device,a continuous thermoelectric conversion device is designed to carry out continuous thermoelectric conversion under realistic conditions,and a continuous power generation experiment is carried out.The experiment shows that the continuous thermoelectric converter can produce6.125?10^-3Jelectric energy in 40min,which is equivalent to the power required by the remote control button 12times.