Research On The Self-excited Pulse Nozzle Used In The Cleaning Of Oil Tank

In allusion to the cleaning technologies of oil tanks in industry at present, a new method that basing on the principle of self-oscillation pulse shooting is first proposed. By the use of the characteristic of pulse shooting, the cleaning system will have a concentrated output of energy on the oil sludge in the bottom of tank, it makes the peak value of beating pressure far bigger than the mean value, and accelerates the liquefaction and break up of the oil sludge, eventually enhance the cleaning efficiency of oil tank .The most important equipment in the method is the new self-excited pulse nozzle, thus the paper will carry out the research in such aspects as the flow field structure in the nozzle, the spray performance of nozzle, the mechanism of pulse shooting and the design of jet system in the method.First of all, a mathematic model which describes the characteristic of flow field inside the nozzle is set up. On the numerical simulation of it, a course that the pulse occurs and develops in a cycle is brought out, which helps to analyze the mechanism and the conditions of the appearance of pulse shooting and find out the two important factors that influence the effect of pulse, namely the interior structure of nozzle and the operating condition.Secondly, the optimization design of the nozzle including the structure parameter and operating conditions is completed through the combination of numerical simulation and the self-excited pulse shooting experiment, meanwhile the optimal structure parameter and operating condition of the nozzle are gained, which makes a good basis for application in the industry; at the same time, the spray performance of the nozzle is discussed, and also the beating pressure of pulse shooting and continuous shooting is compared in the experiment, the result is that the former is much bigger than the latter in value.Then, on the basis of the above analysis, referring to the structure of self-excited pulse nozzle used in drilling in industry, design and improvement have been taken on some location of the model nozzle used in the experiment, eventually a nozzle that can be directly used in engineering is achieved. Combined with a cleaning project whose volume is about 50,000 m~3, the design of the jet system is accomplished. Finally, the summarization of the dissertation is given, the deficiency in the research is pointed out and the suggestions of further researches are also promoted.