| The vortex tube is an energy separation device that can separates the high-pressure airflow into two different airflow with higher temperature and lower temperature.The vortex tube has a simple structure with no moving parts.The vortex is widely used in many fields.At present,there is no unified and profound explanation for the cooling and heating mechanism of the vortex tube.In order to reveal the principle of this thermophysical phenomenon and improve its energy utilization,it is necessary to do the further research from the experimental point of view.The experimental data on the characteristics of the vortex tube are relatively rich so far,but poor on the temperature field research about this device.Most of the research focus on the large flow vortex tube,but the small flow vortex tube is rarely involved.Obtaining the temperature distribution characteristics of the cold and hot fluid separation area in the vortex tube is the purpose of this paper.The operation space of the cold and heat separation area of the small flow vortex tube is very small,so the key is to obtain the small volume thermocouple with less influence on the flow field and high-accuracy temperature measurement ability.Finally install it reasonably.To obtain the temperature distribution in the small flow channel space,the sensor needs high measurement accuracy and fast response characteristics.For this purpose,copper wires and constantan wires with a diameter of 30 ?m are welded by a controlled pulse discharge device.We made the quick-response thermocouple with a joint diameter of 80 ?m,and designed a matching filter amplifier circuit.The self-made thermocouples are calibrated with the linearity nearly 99.99% within 0-95?(273.15~368.15K),and the dynamic response time is about 40 ms.This paper designed and manufactured a micro-motion table that can realize the angle adjustment with a precision of 0.1 degrees and the radial adjustment with a precision of 0.01 mm in cylindrical coordinates.The sensor with this micropositioner can adjust the angle and radial position in the axial section of the vortex tube.An experimental system for measuring the temperature field in the vortex tube was built with the self-made thermocouple as an important measuring device combining the sealing positioning device and the micro-motion table.Based on the law of conservation of energy,a lot of experimental research work was carried out.The compressed air at room temperature provided by the air compressor as the working medium.The pressure-regulated and filtered compressed air flows into the vortex tube and expands into two different temperature airflows.The flow rate and pressure of the cold and hot airflows are measured at the vortex tube inletS and outlets.At the same time,the temperature distribution on the axial cross section is measured using the self-made fast response thermocouple with a micro-motion table.It has been measured that the temperature change along the radial position under the same working condition.The experimental date has a strong regularity.In the axial section,the temperature field distribution profile is clear and the change is obvious.The experimental data is true and reliable,which conforms to the law of conservation of mass and the law of conservation of energy about the vortex tube fluid system.Using Ansys to simulate the fluid flow in the vortex tube of the interpolated thermocouple,it was found that the interpolated thermocouple disturbed the flow field,which caused the flow field near the thermocouple to be more complicated and may cause fluctuations in the temperature measured by the thermocouple.This is consistent with the experimental results... |
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