Numerical Analysis And Experimental Research On The Diesel Ultrafine Atomization Nozzle For Detonation Engine

Detonation engine is a new type of engine,which has broad application prospects and development space.It has the characteristics of high combustion efficiency and less pollution emission.Although the concept of detonation engine was put forward very early and some progress has been made,but it can only be successfully detonated in laboratory environment.But at present,the successful experiments in the laboratory environment are all using gas fuel,and it is very difficult to achieve and maintain detonation successfully using liquid fuel.The main problem is the design of fuel atomization system.Because of the working characteristics of detonation engine,detonation wave propagates very fast in its combustion chamber,reaching the level of several kilometers per second,so its requirement for fuel atomization is very high.The fuel injection system must complete atomization,mixing and evaporation in a few milliseconds,and the diameter of fuel droplets after atomization should reach micron level,then detonation engine can detonate successfully and maintain a stable detonation wave.This has also led to various problems in the practical application of detonation engines.Firstly,a nozzle model is designed based on the theoretical model.Then,the effects of different parameters of nozzle and flow field on fuel atomization particle size and particle size distribution at different injection distances are studied through theoretical analysis,numerical simulation and experimental verification.The main contents of this paper are as follows:The development status of detonation engine,detonation theory,atomization nozzle and atomization theory is summarized.The conditions of fuel atomization system for detonation engine using liquid fuel are analyzed.The theory of computation in Fluent is reviewed.The working principle,atomization characteristics and application scope of several commonly used atomization models are analyzed.The working principle,atomization characteristics and application scope of several commonly used atomization models are analyzed.The optimum atomization model was selected to design the nozzle structure by Fluent numerical simulation,and the nozzle calculation model was established.The effects of nozzle gas path diameter,incoming velocity,flow pressure,flow field temperature,spray angle and fuel supply rate on the atomization effect and the droplet size distribution at different spray distances were calculated respectively.The results obtained by numerical simulation are analyzed by orthogonal test.The orthogonal test table with 6 factors and 5 levels was constructed by selecting 5 representative calculation results from the calculation results of 6 parameters.According to the combination of the parameters in the orthogonal test table,25 numerical simulations were carried out to analyze the magnitude and trend of the influence of six parameters on the atomization effect.The atomization test bench was designed and built.The equipment type was selected according to the parameters,and the atomization effect of the nozzle was tested on the atomization test bench.The atomization effect of the nozzle and the reliability of the calculation model are verified through the test results.