Study On Flow Field And Flame Characteristics Of A Reverse Flow Combustor

Reverseflow combustor is widely used in small aircraft engines,mainly by the flame tube,the inner and outer ring channels and large elbows and other components,its unique airflow through two 180 ° deflection of the structural characteristics has obvious advantages and disadvantages,and it has great significance to research the performance of the reverseflow combustor.In this paper,the flow field and flame characteristics of three kinds of single-head reverseflow combustor were carried out by experiments.According to the inner and outer flame tube jet hole distribution of the reverseflow combustor,and inner and outer ring road,flame tube contour are exactly the same in different reverseflow combustors,the design with skillful connection is adopted,and get the results of the flow field and the flame characteristics with non-contact measurement.Contrast the results of the test,it is concluded:(1)With the increase of the loss of total pressure,the inlet massflow of the reverseflow combustor gradually increases.The inlet massflow of the different reverseflow combustor is quite different when the loss of total pressure is the same;The oil supply pressure has a great influence on the atomization performance of the nozzle.When the oil supply pressure is more than 0.6MPa,the atomization performance of the nozzle is better;Combined with the limitation of the size of the single-head reverseflow combustor and the requirements of the flow field test,the hot hole jet of the light is adopted;(2)The effect of loss of total pressure of the combustor on the non-reaction flow field and reaction flow field is mainly manifested that the flow velocity of each point in the value size increases with the increase of total pressure loss,while the structure of the flow field keep the same;Under the condition of the same total pressure loss,the result shows that the non-reaction flow field has some differences with the reaction flow field.The max velocity of the reaction flow field is higher than the max velocity of the non-reaction flow field,and the result of the reaction flow field reflects the fuel nozzle spray kerosene trajectory in a certain area.;The effect of oil and gas ratio of the combustor on the reaction flow field is not obvious;The structure of the reverseflow combustor on the flow field structure has great influence,it shows the distribution of jet hole affects the location and size of reverseflow area,flow direction and so on.And the diameter of jet hole affects the jet penetration depth and jet velocity.(3)With the same oil-gas ratio,due to the difference of the atomization performance of the centrifugal nozzle in low total pressure loss and high total pressure loss,the structure of the flame is quite different,and the distribution of the combustion intermediate product is obviously different.The area of the core reaction zone increases with the increase of the total pressure loss,and the outlet temperature increases with the increase of the total pressure loss;Oil and gas ratio affect the flame structure and the outlet temperature of the combustor.When the centrifugal atomizer has better atomization performance,the distribution of flame structure and combustion intermediate product is not obvious.When the atomization performance of the centrifugal nozzle is obviously different,the distribution of flame structure and combustion intermediate product are quite different.The outlet temperature increases with the increase of the ratio of oil to gas;The change of the structure of the combustion chamber will obviously change the shape of the flame and the distribution of the combustion intermediate product.In case 1,case2 and case3,the flame expansion angle of the reverseflow combustor gradually decreases and the position of the head in the high temperature zone near the inner ring obviously moves forward,so the structure of the reverseflow combustor has a significant impact on the flame structure;(4)The characteristics of the flow field are closely related to the flame structure,the combustion in the area with strong parallel airflow is more intense.The combustion intermediate product profile is more smooth.As the parallel airflow gradually weakens,the severity of combustion decreases,the combustion intermediate product profile becomes wrinkled,The strength of the parallel airflow in the flow field has a significant impact on the combustion chemistry.