Taking a propfan engine as the research object,the CFD method was used for 3D modeling and unsteady slip flow for numerical calculation.The propfan rotation domain and the nacelle outside flow domain were meshed by us...Taking a propfan engine as the research object,the CFD method was used for 3D modeling and unsteady slip flow for numerical calculation.The propfan rotation domain and the nacelle outside flow domain were meshed by using the partition splicing grid technology.Used the Reynolds⁃averaged of N⁃S equation,the Reynolds stress term uses the RNG turbulence model;and based on the slip grid method,numerical calculation of the flow field with different Mach numbers,front and rear blade angles and engine state were carried out;and the change law of propeller fan characteristics and the influence of slip flow on the inlet flow field were analyzed.The blade angle was the key parameter of the propeller fan characteristic conditions.When the blade angle increases from 41°to 50°,the thrust coefficient increases by 31.2%,and the power coefficient increases by 33.4%;in the climbing state of the propeller fan,the maximum total pressure distortion at the inlet port of 6.8%;the cross section is less affected by the slip flow of the propfan;and the pressure distribution is relatively uniform,but the area of the flow channel is small.The research results can provide a solution for the matching of the counter⁃rotating propeller fan and the engine and the arrangement of the air inlet measuring rake.展开更多
In the mid seventies a new propulsor for aircraft was designed and investigated-the so-called PROPFAN.With regard to the total pressure increase,it ranges between a conventional propeller and a turbofan with very high...In the mid seventies a new propulsor for aircraft was designed and investigated-the so-called PROPFAN.With regard to the total pressure increase,it ranges between a conventional propeller and a turbofan with very high bypass ratio.This new propulsion system promised a reduction in fuel consumption of 15 to 25% compared to engines at that time.A lot of propfans (Hamilton Standard,USA) with different numbers of blades and blade shapes have been designed and tested in wind tunnels in order to find an opimum in efficiency,Fig.1.Parallel to this development GE,USA,made a design of a counter rotating unducted propfan,the so-called UDF,Fig.2.A prototype engine was manufactured and investigated on an in-flight test bed mounted at the MD82 and the B727.Since that time there has not been any further development of propfans (except AN 70 with NK 90-engine Ukraine,which is more or less a propeller design)due to relatively low fuel prices and technical obstacles.Only technical programs in diferent countries are still going on in order to prepare a data base for designing counter rotating fans in terms of aeroacoustics,aerodynamics and aeroelasticities.In DLR.Germany,a lot of experimental and numerical work has been undertaken to understand the physical behaviour of the unsteady flow in a counter rotating fan.展开更多
文摘Taking a propfan engine as the research object,the CFD method was used for 3D modeling and unsteady slip flow for numerical calculation.The propfan rotation domain and the nacelle outside flow domain were meshed by using the partition splicing grid technology.Used the Reynolds⁃averaged of N⁃S equation,the Reynolds stress term uses the RNG turbulence model;and based on the slip grid method,numerical calculation of the flow field with different Mach numbers,front and rear blade angles and engine state were carried out;and the change law of propeller fan characteristics and the influence of slip flow on the inlet flow field were analyzed.The blade angle was the key parameter of the propeller fan characteristic conditions.When the blade angle increases from 41°to 50°,the thrust coefficient increases by 31.2%,and the power coefficient increases by 33.4%;in the climbing state of the propeller fan,the maximum total pressure distortion at the inlet port of 6.8%;the cross section is less affected by the slip flow of the propfan;and the pressure distribution is relatively uniform,but the area of the flow channel is small.The research results can provide a solution for the matching of the counter⁃rotating propeller fan and the engine and the arrangement of the air inlet measuring rake.
文摘In the mid seventies a new propulsor for aircraft was designed and investigated-the so-called PROPFAN.With regard to the total pressure increase,it ranges between a conventional propeller and a turbofan with very high bypass ratio.This new propulsion system promised a reduction in fuel consumption of 15 to 25% compared to engines at that time.A lot of propfans (Hamilton Standard,USA) with different numbers of blades and blade shapes have been designed and tested in wind tunnels in order to find an opimum in efficiency,Fig.1.Parallel to this development GE,USA,made a design of a counter rotating unducted propfan,the so-called UDF,Fig.2.A prototype engine was manufactured and investigated on an in-flight test bed mounted at the MD82 and the B727.Since that time there has not been any further development of propfans (except AN 70 with NK 90-engine Ukraine,which is more or less a propeller design)due to relatively low fuel prices and technical obstacles.Only technical programs in diferent countries are still going on in order to prepare a data base for designing counter rotating fans in terms of aeroacoustics,aerodynamics and aeroelasticities.In DLR.Germany,a lot of experimental and numerical work has been undertaken to understand the physical behaviour of the unsteady flow in a counter rotating fan.
