Research On Working Process And Combustion Performance Of Wave Rotor Combustor

Wave Rotor Combustor is a new kind of unsteady pressurized combustion device and has significantly potential advantages to improve the propulsion system performance.The researches on Wave Rotor Combustor have been mainly concentrated on project demonstration and key technologies.Few efforts were made to its working process and combustion performance.This paper studied the working processes and combustion performance of Wave Rotor Combustor,based on the analysis of its impact on turboshaft engine performance.The main research works and results include:(1)The Wave Rotor Combustor turboshaft engine cycle analysis model was established,and the advantage of Wave Rotor Combustor to improve the overall engine performance significantly is verified.Then a Wave Rotor Combustor aerodynamic scheme was designed by chosen reasonable initial parameters.The research results show that the scheme can achieve temperature and pressure gain by 10.4% and 32% respectively.When hydrogen was used as the fuel,the peak combustion wave pressure was approximately 2 MPa.All these verify the feasibility of the design.Then the Wave Rotor Combustor experimental system was designed.(2)In order to solve the problem of Wave Rotor Combustor ignition,a hot jet igniter was designed for wave rotor ignition,and experimental research was conducted to study its performance.It was concluded that the fuel filling through the tangential hole could achieve lower ignition limit and more wide range of stable combustion,and was identified as the hot jet igniter fuel filling scheme.When a "convergent-divergent-straight " nozzle with 10 mm diameter was used,the Damkohler number is the most suitable for Wave Rotor Combustor ignition.The jet core length is more than 45 mm.Within jet core,the energy presents liner distribution while the momentum shows quadratic distribution with respect to mass flow rate.(3)A motionless premixed Wave Rotor Combustor experimental system was established to verify the practicality of designed igniter.The results showed that the designed igniter can ignited Wave Rotor Combustor reliably.It also found that when nozzle outlet distance from wave rotor passage is 38 mm adverse to the ignition.The combustion pressure gain was obtained at a premixed gas equivalence ratio of.The equivalence ratio has a decisive influence on flame frontal tilt.(4)To reveal the detailed work process of Wave Rotor Combustor,the rotary inlet and outlet ports type Wave Rotor Combustor experimental system was established.Experimental studies have found that the Wave Rotor Combustor work steadily with the filling velocity of ~ m/s,and with the equivalence ratio range about ~.The peak pressure value during combustion process reaches up to 0.73 MPa.Generally,increased with the increase of the filling velocity,and decreased with the increase of equivalence ratio.Combustion pressure peak value increases with the increase of wave rotor rotation speed and equivalence ratio.The unrepeatable index of Wave Rotor Combustor cycle presents reciprocal relationship to the combustion pressure peak value.Due to the leakage,chemical reaction area expansion speed increase rapidly with the increase of wave rotor speed.Its slope relative to the time increasing rapidly from 0.05 in 900 rpm to 0.195 in 1500 rpm.The equivalence ratio has remarkable influence on the flame shape.The flame front tilts to the concave surface at a low equivalence ratio,while the equivalence ratio increased to a certain value,the flame tilt direction change.And the critical value decreases with the increase of wave rotor rotation speed.(5)Experiment studied the influence of three kinds of inlet and outlet ports relative position on Wave Rotor Combustor combustion performance.Under the action sequence Ⅰ,the widest work range was obtained.The influence of combustion strengthening device on Wave Rotor Combustor combustion performance were explored with the blockage ratio of 18% and 28%.It was found that when the flame propagate through the blockage,combustion peak pressure increase and the flame propagation velocity increase rapidly up to 100 m/s.(6)To explore coordination problem of channels,a dual-channel rotary internal Wave Rotor Combustor experimental system is established and the structure strength is verified.One of the channels can worked stability by experimental test.While another channel working process existed the instability because of the back pressure influence of the previous channel.Combustion performance increases with the increase of filling velocity and equivalence ratio.Finally the numerical method was adopted to analyze the centrifugal force effects on Wave Rotor Combustor combustion characteristic.According to the researches,the working process of Wave Rotor Combustor was preliminary showed.Key technologies such as fuel filling and hot jet ignition were mastered.The rule of flame propagation and development and pressure gain change with respect to wave rotor rotation speed and boundary conditions etc were obtained.The results established foundation for the further research of wave rotor Combustor.