| In the backdrop of the energy crisis and the pollution of the environment, energy conservation and emission reduction is a hard task before us. Scroll expand machine, as a key component of the waste heat recovery system, and also a kind of zero emission power machinery, with the good performances of high efficiency, high reliability, low vibration noise and compact structure, gets more and more attention in recent years.In order to research on the thermal characteristics scroll of expand machine, beginning with the geometry of vortex machines, this paper have discussed the mechanical structure and working principle of the scroll expand, pointed out the characteristic parameters of the scroll expand and the calculation method of the suction and discharge volume. And based on the common engineering thermodynamics theory, derived the basic thermodynamics indexes of the expansion rate and theoretical work of the scroll type. Then introduce the concept of the pneumatic power, and definition the effective heat efficiency of scroll expander and volume efficiency.On the basis of theoretical analysis, we design a test bed to test the characteristics of scroll expand. This article introduced all of the hardware equipments of the test bed, from the air source generator, the air control pipe section, the dynamometer machine, the data acquisition system parts to the sensors. Then using the ADAM4000series data acquisition card the data acquisition system collects and uploads the output signal from the pressure, temperature and flow sensors. At the same time, gives the design of the front panel and background program based on the Lab VIEW virtual instrument. Verify that calling RS232serial ports and operating SQL Server database in LabVIEW is feasible.In the test bed, adopting the experiment method of fixing the valve opening and changing the load and the speed, carried out the test on the scroll expand repeatedly. The tests indicate that most characteristics of the scroll expand are relevant with its rotating speed, and with the speed growth, the volume efficiency, effective thermal efficiency and the torque characteristic are all significantly better. It is because the internal leakage of the scroll expand lessen in high speed. Therefore, point out that an appropriate increase in the work speed or try to reduce the internal leakage is kind of important measures to improve the working performance of the scroll expand. |
