Study On The Optical Feature Of Outflow Field And Atomization-combustion Characteristics Of Attitude And Orbital Control Engine

With the improvement of rocket engine performance requirements,thrust chamber works at the condition of a higher temperature and pressure.Therefore,accurate and timely monitor and diagnosis of atomization and combustion is very important.The engine tail flame spray field image contains the characteristics about the status of atomization and combustion.And the characteristics of the tail-spray field image have a quasi-real-time characteristic for the monitoring of the atomization combustion state.Therefore,it is very important to study the relationship between the image characteristics of the engine tail spray field and the atomization injection state of the engine.This topic is based on the afterburning on flow field of a type of multi-hole impinging engine in hot firing tests.Afterburning refers to the continued combustion of the spray flame when the engine spray and the external flow field are mixed with each other.Firstly,the PDPA experimental system was used to study the parameters of the atomization field of the impinging injector.Then,an integrated simulation model of three-dimensional unsteady thrust chamber evaporation-combustion-tail smoke field was established by combining atomization test and thermal test.Then,through the tail image recognition technology,combined with the simulation model and the thermal test data,the mapping relationship between the characteristics of the engine tail image and the atomization injection parameters is established,which provides a new method for the monitoring and diagnosis of engine atomization combustion.Finally,the simulation model of the flaring field of the engine is studied by using the tail model simulation model.Through the quantitative identification and qualitative observation and analysis of the characteristics of the tail flame image,The reason of the afterburning was diagnosed.It is verified that too much small fuel molecules is the direct cause of the afterburning,such as H2,CO and so on.The reaction of these small molecules with oxygen in the tail smoke field leads to the afterburning,the root cause may be a larger percentage of the cooling capacity of the zone.The paper mainly carries out the following work:1.The PDPA experimental system was used to study the parameters of the atomization field of the impinging injector,and analyzed the distribution characteristics of droplet size,velocity and flow intensity in the atomization field,and reached the law of the atomization characteristics of some injectors.2.Based on the results of PDPA experiment,coupled the process of evaporation,combustion and heat transfer,andbased on the results of the hot firing tests.,a 3D unsteady thrust chamber was established.This model achieved the accurate simulation of inside and outside the flow field,For the engine to optimize the design and troubleshooting to provide accurate simulation path.3.Based on the simulation model of the thrust chamber evaporation combustion tail flame field and the tail infrared image feature recognition method,this title studied the relationship between the engine injection state and the infrared image feature of the tail flame injection field.It is known that different characteristics of infrared image of tail spray field(such as the gray value entropy,perimeter and area of the first Mach locus,the tail flame exit zone and the tail flame jet zone in the infrared image of the tail fire field)are different for different engine atomization injection parameters(such as: droplet ejection speed,droplet average particle size,side to cool the flow percentage).Therefore,different atomization spray parameters can be selected to monitor the engine spray atomization state.4.Based on a certain type of DC engine tail flame jet edge obvious expansion phenomenon,the simulation model of the flaring field of the engine is simulated by the tail model simulation model.Through the quantitative identification and qualitative observation and analysis of the characteristics of the tail flame,diagnosed the reasons for the afterburning on flow field.It is verified that too much small fuel molecules is the direct cause of the afterburning,such as H2,CO and so on.The reaction of these small molecules with oxygen in the tail smoke field leads to the afterburning,the root cause may be a larger percentage of the cooling capacity of the zone.