The Study Of Flow Characteristics Of Vortex Generators Used In Rectangular Channels Of V-type Ultrasonic Heat Meters

With the development of science and technology, and the lack of resources, the word "energy-saving" has become keywords in today’s researching. As an instrument of heat measuring, its energy-saving effect visibly. But heat meters had a very short time of development in our country and there are a lot of unsolved problems. The ultrasonic signals were reflected by the internal surface below of V-type ultrasonic heat meter. Because of the problem of water quality, sediments will appear on the internal surface below during a long period. This article proposes a thought of putting a vortex generator in rectangular channels of V-type ultrasonic heat meter aims at the problem of sediments. The advantage of putting a vortex generator is that it can produce longitudinal vortex to scour the internal surface below and this can improve the problem of sediments effectively. In this way, the quality of ultrasonic signal’s reflex is improved. So the purpose of improving the measurement accuracy of ultrasonic heat meter is achieved.In this article, I do some research on the flow characteristics of vortex generator used in the rectangular channels of V-type ultrasonic heat meter with appropriate mathematical model for numerical simulation and give out the graphs of changing situation of meter factor (K factor) under different quantity of flow points and also gives the result of the numerical simulation of flow field velocity vector diagram and the constant velocity chart to explain the vortex generator’s influence on flow characteristics in the rectangular channels. My study puts forward a new way on the ultrasonic heat meter of the ultrasonic heat meter and it is very helpful to the to improve the measurement accuracy.In this paper, we obtained the following conclusions:(1) According to the graph of the of K factor’s transformation, we could find that the K factor’s changing-trends is almost the same under different flow points. But it is a little difference between the flow point0.05m3/h with other flow points. It reflects the difference between laminar and turbulent flow velocity distribution.(2) According to the distribution of velocity circulation under different z coordinate, the vortex phenomenon is easier to observe in the area of closer to the inside surface below(3) From the distribution chart of velocity we can see that the velocity distribution has a little difference under different flow points;(4) Under different Re, K factor’s transformation is unstable during the process of Laminar to turbulent. Actual performance is the measurement error around0.05m3/h flow point rise and fall frequently.(5) The different propagation path of ultrasonic affects the position of vortex generator and the area of vortex will different. The ultrasonic signal’s reflection is not a point but an area, the vortex generator will away the reflecting region with magnify of incident. And the cleaning effect of vortex generator will be reduced. On the contrary, with the decrease of incident angle, propagation path of ultrasonic signal is too short and this is not good for gathering the velocity information.