Experimental Study And Analysis Of Spiral Flow In Pipes

Spiral ( swirling ) flow is a sort of special and regular vortex movement. Spiral flow is widely used in industry, e.g. in jet technology, combustion technology, pneumatic transportation, cyclone separators. Researchers have done a lot of investigations about spiral flow. Moreover, spiral flow can be seen frequently in nature, such as tornado. Once we master the rules of spiral flow, we can develop better capability and better efficiency spiral flow generators. This has evident engineering value and important economy value. In general, spiral flows in pipes are generated by several means: fixing revolving-flow implement, guiding fluid by vanes with a certain angle, tangentially ejecting, and axially rotating pipe. They aren't in the range of our research. Prof. Horii has invented three new types of spiral flow generators. They are applied in area of engineering practice. In this paper ,we depicted the actuality and background of this type of spiral flow,illustrated the important significance of its applications in engineering and basic theory. We designed and manufactured two sorts of radial spiral flow generators by reference to kinds of spiral flow generators, especially Prof. Horri's invention. Using the set of generators, we researched the theory and experiment of spiral flow, pondered the mechanism of spiral flow, and educed our conclusion.By means of experimental measurements, development and formation of the spiral flows in pipes were studied in this dissertation. Also the influence of kinds of parameters and entrance condition were investigated. During the experiment, we measured the velocity distributions of spiral flow generated by our equipments, partly mastered the characters of spiral flow; we studied the influence of generator's geometry parameters to spiral flow, and found the best combination of many parameters about spiral flow. We deduced the theoretical computing formula about attenuation of spiral flow intensity in our test. We got the exponent attenuation rule of spiral flow, partly mastered the rules of spiral flow movements. The mechanism of spiral flow was supposed. We thought thatthe flown line's distortion to the same direction is one of necessary condition to spiral flow. The mechanism of spiral flow we deduced can explain many phenomena , we prepare to declare patent of the set of spiral flow generator which invented in the paper. Our conclusion is based on experiment, it can offer foundation to advanced research.