7A04铝合金等温挤压某航空轮工艺与性能研究

针对航空轮的结构特征,设计了等温成形工艺方案。采用7A04铝合金进行了试验,并对锻出的航空轮进行了力学性能检测。结果表明,其抗拉强度最高为585MPa,最低为517MPa,屈服强度最高为519 MPa,最低为466 MPa,力学性能优良。

Simulation and analysis of humid air turbine cycle based on aeroderivative three-shaft gas turbine

Due to the fact that the turbine outlet temperature of aeroderivative three-shaft gas turbine is low,the conventional combined cycle is not suitable for three-shaft gas turbines.However,the humid air turbine(HAT)cycle provides a new choice for aeroderivative gas turbine because the humidification process does not require high temperature.Existing HAT cycle plants are all based on single-shaft gas turbines due to their simple structures,therefore converting aeroderivative three-shaft gas turbine into HAT cycle still lacks sufficient research.This paper proposes a HAT cycle model on a basis of an aeroderivative three-shaft gas turbine.Detailed HAT cycle modelling of saturator,gas turbine and heat exchanger are carried out based on the modular modeling method.The models are verified by simulations on the aeroderivative three-shaft gas turbine.Simulation results show that the studied gas turbine with original size and characteristics could not reach the original turbine inlet temperature because of the introduction of water.However,the efficiency still increases by 0.16%when the HAT cycle runs at the designed power of the simple cycle.Furthermore,simulations considering turbine modifications show that the efficiency could be significantly improved.The results obtained in the paper can provide reference for design and analysis of HAT cycle based on multi-shaft gas turbine especially the aeroderivative gas turbine.

Effect of Heat Loss on Laminar Flamelet Species Concentration

The effects of heat loss on the structure of laminar flamelets,which are the constitutive elements of turbulent flames under the most common operating conditions,are investigated for typical aeronautical gas-turbine operating conditions at take-off.The magnitude of heat loss is quantified via the "enthalpy defect" measured with respect to an adiabatic flame.A procedure to generate laminar flamelets with an assigned enthalpy defect at the boundaries is devised and applied to nonpremixed propane/air flames,as propane reproduces the essential features of higher hydrocarbon combustion.It is found,contrary to commonly held beliefs,that the enthalpy defect has a significant effect on the concentration not only of minor species,but also of main reaction products.Such effects are found in general to be more pronounced for fuel-rich conditions.An impact is anticipated on the formation rate of nitric oxides.The effects of scalar dissipation rate are also discussed.

Aerodynamics Design of Two-stage Vane-less Counter-rotating Turbinec

It is one of the most efficient ways to greatly improve aero-engines' performance by utilizing vaneless counterrotating turbine(VCRT) technology.To supply sufficient power,VCRT turns to be high Mach number,large flow angle at high-pressure turbine(HPT) rotor exit,and low blade camber angle,which increase difficulties to turbine design.As the axial velocity ratio of HPT rotor is much larger than the conventional ones,the optimal selection of VCRT velocity triangles based on theoretical analysis is developed,and how the efficiency varied by HPT stator/rotor exit flow angle is also figured out.The key points to design a high efficient practicable VCRT are to select velocity triangles that are characterized by low flow coefficient,high outlet flow angle and large axial velocity ratio of HPT rotor.Meanwhile,performance comparison between convergent blade and convergent-divergent blade shows the latter is more appropriate for VCRT.

Effects of Rising Angle on Upstream Blades and Intermediate Turbine Duct

With the improvement of requirement,design and manufacture technology,aero-engines for the future are characterized by further reduction in fuel consumption,cost,but increment in propulsion efficiency,which leads to ultra-high bypass ratio.The intermediate turbine duct(ITD),which connects the high pressure turbine(HPT) with the low pressure turbine(LPT),has a critical impact on the overall performances of such future engines.Therefore,it becomes more and more urgent to master the design technique of aggressive,even super-aggressive ITDs.Over the last years,a lot of research works about the flow mechanism in the diffuser ducts were carried out.Many achievements were reported,but further investigation should be performed.With the aid of numerical method,this paper focuses on the change of performance and flow field of ITD,as well as nearby turbines,brought by rising angle(RA).Eight ITDs with the same area ratio and length,but different RAs ranges from 8 degrees to 45 degrees,are compared.According to the investigation,flow field,especially outlet Ma of swirl blade is influenced by RA under potential effect,which is advisable for designers to modify HPT rotor blades after changing ITD.In addition to that,low velocity area moves towards upstream until the first bend as RA increases,while pressure loss distribution at S2 stream surface shows that hub boundary layer is more sensitive to RA,and casing layer keeps almost constant.On the other hand,the overall total pressure loss could keep nearly equivalent among different RA cases,which implies the importance of optimization.

Aero-Thermal Performances of Leakage Flows Injection from the Endwall Slot in Linear Cascade of High-Pressure Turbine

The existence of a gap between combustor and turbine endwall in the real gas turbine induces to the leakages phenomenon. However, the leakages could be used as a coolant to protect the endwaU surfaces from the hot gas since it could not be completely prevented. Thus, present study investigated the potential of leakage flows as a function of film cooling. In present study, the flow field at the downstream of high-pressure turbine blade has been investigated by 5-holes pitot tube. This is to reveal the aerodynamic performances under the influenced of leakage flows while the temperature measurement was conducted by thermoehromic liquid crystal （TLC）. Expe- rimental has significantly captured theaerodynamics effect of leakage flows near the blade downstream. Further- more, TLC measurement illustrated that the film cooling effectiveness contours were strongly influenced by the secondary flows behavior on the endwall region. Aero-thermal results were validated by the numerical simulation adopted by commercial sottware, ANSYS CFX 13. Both experimental and numerical simulation indicated almost similar trendinaero and also thermal behavior as the amount of leakage flows increases.