Performance Analysis Of The Staggered Form Of An Ejector With Tabs

The gas turbine has the advantages of large power,light weight and small size,Modern large warships are usually powered by gas turbines,Because of the high temperature and high flow rate of the marine gas turbine,If you do not take the necessary cooling measures,the engine room temperature will is too high,is not Advantageous to the normal operation of personnel and equipment,The infrared suppression of military ship exhaust is very important to the survival of naval ships under modern naval warfare.in the majority of cases,adding ejector in ship exhaust system is an economical and reliable way,Principle of exhaust ejector is very simple,which utilizes high temperature and high pressure main engine exhaust to pump the cold air in the atmosphere,in order to achieve low temperature mixing gas.There are a variety of programs can be applied to the injector.According to the research results of other scholars,a new design scheme is presented in this paper,installing staggered arrangement of vortex generators at outlet of exhaust pipe is the new scheme.The author uses the computational fluid dynamics software to implement this idea.By a large number of numerical simulation.Getting a series of results,in this way,we know the influence of various geometric vortex generators on the ejector performance.The main research is as follows:1.Before the numerical simulation of the new vertex scheme,Referencing the experimental data and geometric model of Asim Maqsood doctoral dissertation,The numerical simulation of the 22.5 degree bend ejector was carried out by using five kinds of two equation turbulence models.the author establishes the same geometric model and utilize different turbulence models to simulate the exhaust ejector,Research shows that Realizable k-? is more consistent with the experimental data,so using this turbulence model in further numerical simulation.2.Based on the model of 22.5 degree elbow ejector in Asim Maqsood doctoral dissertation,referencing its main geometric features,the author designs an exhaust ejector with a 90 degree turn in line accord with the actual characteristics of warships.In order to get the performance parameter to change the swirl angle of the main inlet,the numerical simulation is carried out with FLUENT in the cold and hot state.Compared with the ejector with a staggered tabs.3.Based on the 8 piece,30 degree of installation angle,the effective blocking area of the ejector with Triangular tabs is 13%.To design the ejector in the form of the gradual change of the stagger angle.In the form of triangular and trapezoidal tabs,the ejector performance parameters are obtained and are compared by numerical simulation.4.In addition,the calculation of symmetric staggered ejector is carried out.The tabs is triangular.Changing the angle of tabs.The performance parameters of the cold and hot state are calculated to get the performance curves.By comparison,it is found that the staggered ejector has the characteristics of high cooling efficiency.