级间引气对一维方案压气机流道和性能的影响

本文研究了GE公司的高效节能发动机(E3)压气机在不同引气方案下,其流道形状和性能的变化规律。采用改进的压气机一维方案计算程序,将级间引气模块加入该程序中并进行了验证,结果表明其可较准确计算E3压气机的流道形状和特性。在此基础上,选取了三组级间引气量方案,利用该程序计算并比较了不同方案的流道形状变化和性能改变,得出结论:随着引气量的增加,流道面积将稍微减小,压气机效率和压比将有较大降低;为了提高压气机一维方案设计和特性计算的精度,必须在程序中考虑引气量的影响。     

基于扩压因子流型的压气机快速性能预测算法

为快速、准确地获得压气机性能参数、完成压气机性能预测,实现压气机优化设计,基于流线曲率法,将扩压因子作为控制方程、损失模型、熵增修正模型及落后角模型中的关键参数,建立轴流压气机性能快速预测算法。利用该算法对某跨音速轴流压气机性能参数进行计算,并将计算结果与主流商业软件计算结果及试验数据进行对比。通过对比发现：该算法计算效率高,能够快速且较为准确地完成压气机整体性能和沿叶高方向流场参数的预测;计算范围广,在不同转速、不同流量等非设计工况下算法预测结果均与试验及数值模拟数据接近;所选取与完善的经验公式合理可靠,能够较好地描述压气机内部流动。     

压气机分层优化气动设计体系研究

基于压气机分层次气动优化设计思想,结合了优化算法、CFD(计算流体力学)技术与压气机气动设计程序,利用商业软件,建立了压气机气动优化设计平台,将气动优化设计思想融入到了压气机气动设计多个阶段,以实现压气机气动设计使性能最优化的目的.应用商业通用优化平台进行了轴流压气机一维、S2反问题气动优化设计,并采用NUMECA提供的全三维优化设计平台对压气机进行了全三维气动优化设计.计算结果表明:分层气动优化设计是提高压气机气动性能的有效手段,先进的优化算法在气动设计的各阶段都能够比传统设计手段更大限度地实现压气机性能的最优化.     

多级压气机改进设计的性能试验

针对某型多级压气机的改进设计进行性能试验,验证了两种一维计算程序在多级压气机特性预估方面的能力,对比了压气机改进设计前后性能特性的变化,并对其内部流场测量结果进行了初步分析。试验结果表明:一维计算特性与试验特性吻合较好;改进后的压气机在总级数减少一级的基础上,不但保持和提高了原型机设计转速时的高效率和高喘振裕度,并且较大幅度地改善了中低转速时的性能,改进设计工作是成功的。     

多级轴流压气机一维性能预测程序开发及应用

为了实现对轴流压气机气动性能的准确预测,基于平均流线法建立了多级轴流压气机一维气动性能预测方法,编制了相应的Matlab程序,该方法允许针对不同类型压气机选择适用的经验模型。通过计算得到了某四级亚音速轴流压气机和某八级高速轴流压气机的气动性能,对比分析发现,一维性能预测结果与实验/三维CFD模拟结果吻合较好,效率与压比计算偏差均保持在较小范围内,预测结果精度较高。为进一步提高压气机气动性能预测的准确性,发展了一种经验模型自动校准方法,采用该方法对选取的四级亚音速轴流压气机和八级高速轴流压气机模型进行校准,校准后对各转速下气动性能的预测精度均有所提高。研究工作表明,所建立的多级轴流压气机一维气动性能预测方法以及模型自动校准方法具有一定的准确性和可靠性。     

压气机蜗壳通道中气流流动的数值模拟

利用任意拉格朗日 -欧拉 (AL E)计算方法对基于“等环量”理论并考虑气体粘性而设计的蜗牛式压气机蜗壳进行了数值模拟。模拟计算结果与试验所测得的结果基本吻合 ,证明利用本计算程序所进行的数值模拟是可行的 ,计算结果对蜗牛式压气机蜗壳的优化设计具有参考价值     

离心式压气机变工况性能计算

本文对涡轮增压器的主要部件——离心式压气机在变工况下的流量特性、效率特性的计算进行了探讨,并分析了在喘振线上一些参数的变化规律。1)性能计算是基于理想气体一元定常流动的假设之上的。用质量守恒、能量守恒等基本关系式推导出有关计算公式,并通过计算比较,确定了适当的损失模型。在已知有关几何参数的条件下,将带无叶扩压器的离心式压气机依工质的流程划分为5个计算站位,依次计算各站位上的热力参数,最终求出流量、效率特性。按上述计算方法与步骤编制了计算程序,在计算机上对数种型号的离心式压气机进行了计算。主要输入参数有:各计算站位的流道截面积、叶轮进出口叶片构造角等几何参数;大     

亚音速轴流式压气机的特性计算

本文综合了亚音速压气机叶栅试验数据,建立了叶栅落后角、叶栅损失、通流面积阻塞系数和减功系数等随工况参数的变化关系,并用完全径向平衡法及平均截面计算法编制了多级轴流式压气机的特性计算程序。用这两种方法计算了四台压气机,与试验特性相比,在百分之六十设计转速以上,流量偏差一般不大于2％,效率偏差不大于1.5％。同时也表明,只要使用相同的变工况模型,在轮毂比大于0.7时,这两种计算方法所得结果很接近。     

基于经验方程的船用三轴燃气轮机压气机特性计算

针对在压气机特性拟合计算中存在的部件特性不完整问题,提出一种基于经验方程的船用三轴燃气轮机压气机特性计算方法。通过经验方程的引入,求解出所缺少的高压压气机特性方程,继而建立了完整的压气机特性计算模型。分析表明该模型具有较高的精确度,能够满足船用三轴燃气轮机压气机变工况特性计算的需要。     

径流式时轮机械子午流动的边界元计算

采用边界元法求解径流式叶轮机械子午流动问题。通过所编制的程序，对三种离心式压气机进行了计算。计算结果与实验数据比较接近，展示边界无法具有较好的实用性。图５参５     

Temperature field analysis of tangential clearance leakage flow for scroll compressor based on fuzzy ridgelet finite element method

To improve the computing precision and efficiency of temperature field analysis in tangential clearance of scroll compressor, the ridgelet finite element method is combined with fuzzy finite element method to construct the fuzzy ridgelet finite element method of analyzing temperature field in tangential clearance. First, the related research progresses on heat transfer of scroll compressor, wavelet finite element method, and fuzzy finite element method are summarized. Second, the leakage flow model of tangential clearance in scroll compressor is studied in depth. Third, the heat transfer model of leakage flow in tangential clearance of scroll compressor is established, and then the fuzzy ridgelet finite element model is constructed, the fuzzy finite element model is transformed to the random model based on information entropy, the corresponding calculating procedure is designed. Finally, the simulation analysis is performed based on fuzzy finite element method, fuzzy Daubechies wavelet finite element method, and the fuzzy ridgelet finite element model, respectively, comparing analysis between simulation and test results shows that the fuzzy ridgelet finite element method has best computing effectiveness on temperature field analysis of tangential clearance of scroll compressor. In addition, the tangential clearance temperature of scroll compressor with and without water cooling has been analyzed based on the fuzzy ridgelet finite element method, and the results show that the water cooling system can reduce the temperature in tangential clearance greatly.     

Study on heat transfer of leakage flow in tooth tip clearance for single screw compressor based on fuzzy contourlet finite element method

Heat transfer of leakage flow in tip clearance will reduce the working performance, and therefore it is necessary to study it in depth. To improve the computing effectiveness of heat transfer of leakage flow in the tooth tip clearance of the single-screw compressor, the fuzzy contourlet finite element model is constructed by combining the contourlet finite element method and fuzzy finite element method. First, the related research progresses are summarized. Second, heat transfer model of leakage flow in the tip clearance of single-screw compressor is constructed. Third, the fuzzy contourlet wavelet finite element model is established. Finally, heat transfer simulation of leakage flow in the tip clearance of single-screw compressor is performed, and the variables with fuzziness are chosen, which are transformed to random variables based on information entropy theory. The comparing analysis among simulation analysis and test results is performed, and results show that the contourlet finite element method has highest computing precision and efficiency. In addition, the temperature of leakage flow in the tip clearance (L1) is also obtained, and results show that the fuzzy contourlet wavelet finite element method can effectively obtain the temperature distribution rules with fuzziness.     

Optimisation of screw compressors

Increasing demands for more efficient screw compressors require that compressor designs are tailored upon their duty, capacity and manufacturing capability. A suitable procedure for optimisation of the screw compressor shape, size, dimension and operating parameters is described here, which results in the most appropriate design for a given compressor application and fluid. It is based on a rack generation algorithm for rotor profile combined with a numerical model of the compressor fluid flow and thermodynamic processes. Some optimisation issues of the rotor profile and compressor parts are discussed, using 5/6 screw compressor rotors to present the results. It is shown that the optimum rotor profile, compressor speed, oil flow rate and temperature may significantly differ when compressing different gases or vapours or if working at the oil-free or oil-flooded mode of operation. Compressors thus designed achieve higher delivery rates and better efficiencies than those using traditional approaches, which is illustrated in an example of the 3/5 screw rotors designed for a family of dry air compressors, produced and marketed by a renown British compressor manufacturer.     

高原车用增压器离心式压气机特性的修正转换及其探讨

本文基于等效管流模型,提出了离心式压气机特性的Re数修正方法;建立了压气机高原准相似特性及其转换方法.文中还探讨了压气机高原特性的变化规律,并澄清了有关问题.     

几何参数变化对离心压气机性能影响的仿真研究

采用离心压气机性能仿真数学模型研究某些几何参数，如叶片顶部间隙，叶轮叶片出口角变化对压气机性能产生的影响，是当今设计高压比、宽工作范围、高效离心压气机的关键步骤。为此，首先建立了离心压气机性能仿真数学模型。为了验证数学模型的有效性，对Krain叶轮性能进行了计算。随后，对不同叶片顶部间隙，不同出口叶片角的压气机性能进行仿真研究。研究结果表明，随顶部间隙的增大，压气机效率及压比下降；后弯叶轮性能优于径向叶轮。     

Optimum design of a subsonic axial-flow compressor stage

The design of an axial-flow compressor stage for subcritical Mach numbers has been formulated as a non-linear multi-objective mathematical programming problem with the objective of minimizing the aerodynamic losses and the weight of the stage, while maximizing the compressor's stall margin. Aerodynamic as well as mechanical constraints are considered in the optimization solution. The prediction model for estimating the performance characteristics, such as efficiency, weight and stall margin, of the compressor stage is presented. The present design optimization procedure can be applied to a multi-stage compressor.     

The effect of variable stator on performance of a highly loaded tandem axial flow compressor stage

Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds.Considering the high aerodynamic load effects and structural concerns in the design process,it is possible to obtain higher pressure ratios compared to conventional compressors.However,it must be noted that imposing higher aerodynamic loads results in higher loss coefficients and deteriorates the overall performance.To avoid the loss increase,the boundary layer quality must be studied carefully over the blade suction surface.Employment of advanced shaped airfoils (like CDAs),slotted blades or other boundary layer control methods has helped the designers to use higher aerodynamic loads on compressor blades.Tandem cascade is a passive boundary layer control method,which is based on using the flow momentum to control the boundary layer on the suction surface and also to avoid the probable separation caused by higher aerodynamic loads.In fact,the front pressure side flow momentum helps to compensate the positive pressure gradient over the aft blade's suction side.Also,in comparison to the single blade stators,tandem variable stators have more degrees of freedom,and this issue increases the possibility of finding enhanced conditions in the compressor off-design performance.In the current study,a 3D design procedure for an axial flow tandem compressor stage has been applied to design a highly loaded stage.Following,this design is numerically investigated using a CFD code and the stage characteristic map is reported.Also,the effect of various stator stagger angles on the compressor performance and especially on the compressor surge margin has been discussed.To validate the CFD method,another known compressor stage is presented and its performance is numerically investigated and the results are compared with available experimental results.     

Search for Compromise Solution of the Multistage Axial Compressor‘s Stochastic Optimization Problem

The aim of this paper is to discuss a method of the compromise region determination for the multistge axial flow compressor stochastic optimization problesm.This method is based on the 2-D axisymmetrical mathematical model of the compressor and on the new multicriteria optimization procedure .A specific feature of the multicriteria optimization procedure is a possibility to obtain a set of the Edgeworth-Pareto optimal solutiona within the frame of single optimization task.The paper presents some expamples of the compressor‘s geometrical parameters multicriteria optimization.     

Search for Compromise Solution of the Multistage Axial Compressor's Stochastic Optimization Problem

INTRODUCTIONThecurrentmultistagehoalflowcompressorsde-signingandmodifyingprocessesarecloselyalliedwithalotofoptimizationproblemssolution.Thissituationisattributedtodesigner'snaturalaspirationforthe"best"designselectionfromasetoffeasibledesigns.Tillrecelltlythedesigner'sexperienceandintuitionplayedakeyroleinsearchforthe"best"design.Withthecurrefltlevelofcompressor'scomplexity,largenumberofdesign-pointparametersandgasdynamicperfectionisnecessarytouseanumericalop-timizationmethodtoaidthedesi…     

Pressure drop optimisation in debottlenecking of heat exchanger networks

Process integration technology is now widely applied in grass-roots design, energy saving retrofit and the debottlenecking of heat exchanger networks. This technology has been used in a variety of industries and proved to be reliable and applicable in engineering design. Debottlenecking may apply to a specific part or entire unit, whether it is due to increased throughput or process modifications. One of the advanced methods for debottlenecking that is currently used is based upon fixed allowable pressure drops, through which a retrofit can be achieved without a need for pump and/or compressor replacement. This research is trying to develop a new procedure for pressure drop optimisation in debottlenecking. This procedure enables the designer to study pump and/or compressor replacement whilst at the same time optimising the additional area and operating cost of the network. It deals with the problem of optimal debottlenecking of heat exchanger networks considering minimum total cost. Moreover, one can consider the possibility of the replacement of a given pump with a smaller one. The new procedure has been effectively applied to a crude oil pre-heat train, which was subject to some 20% increase in throughput, and the corresponding results proved to be accurate enough.