航空发动机高压压气机吸雨特性分析

为了评估高压压气机吸雨对其气动性能的影响,利用压气机一维计算方法,结合能够反映气水混合物在压气机内部流动物理现象的两相流计算模型,以E3十级高压压气机为研究对象,在来流含水的状态下进行了一维特性计算,研究分析了不同含水量对压气机气动性能的影响。研究结果表明:水滴粘附在叶片表面形成的水膜及水在流动过程中的蒸发作用对压气机性能存在不可忽视的影响。     

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。     

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。     

多级轴流压气机级间引气的数值模拟研究

以某多级轴流压气机的中间级为研究对象,研究了外机匣端壁处级间引气对压气机总体性能及局部流场的影响.根据要求的最大引气量,设计了矩形、圆形及异形三种不同的引气槽结构,并对流场进行了详细的数值计算.结果表明,本文所设计的矩形和圆形引气槽对压气机总体性能及主流流场的影响基本相同,其中,矩形槽造成的引气损失小于圆形槽;异形引气...     

舰船大功率轴流压气机气动设计研究

基于建立的舰船大功率多级轴流压气机气动设计体系,开展了舰船用某型大功率燃气轮机压气机设计研究,完成了6级轴流压气机的气动设计。进行了一维反问题设计、一维特性计算分析、S2反问题计算、叶片造型以及三维CFD计算分析。各级载荷分布从前面级到后面级逐渐降低,叶展方向按照等压比分配以避免径向掺混损失过大,S2设计并没有严格遵循传统的设计规律(等环量、等反动度等),而是基于一维设计方案通过不断调整优化获得的。根据CDA的特点,开发了可用于工程应用的叶片造型程序,可实现不同中弧线、不同厚度分布调节,能够实现叶片弯、掠等功能。三维数值模拟结果表明,考虑动叶叶顶具有0. 5 mm间隙的情况下,6级压气机设计点效率达到89. 75%,设计转速下的喘振裕度为22. 5%,同时具有较好的变工况性能。     

内部通道肋片结构对Mark Ⅱ叶片冷却性能影响的降维模型研究

一维冷却通道气热耦合计算是分层涡轮叶片冷却结构设计的重要方法。发展了以管道网络算法为核心的内部冷却特性计算程序,并与三维传热计算进行了耦合。通过与MarkⅡ叶片特定实验工况下的结果进行对比,验证了方法的有效性。此外,进一步将带肋结构流道传热特性相关经验公式集总在一维气热耦合算法中,分析了带肋通道改型的MarkⅡ叶片冷却性能。结果显示,带肋结构相比光滑流道能显著提升换热性能,在中径截面处较原方案温度下降15～30 K。     

基于通用级特性图的压气机特性计算方法

为了简化燃气轮机建模与仿真中的压气机特性计算,介绍了一种使用通用级特性曲线的计算方法,讨论了级特性图中参考系数的选取对计算精确性的影响,并应用优化后的通用级特性图,对某多级轴流压气机的设计点和非设计点进行了计算,预估出其总特性线,计算结果与原级特性的结果符合良好,验证了该级特性在压气机特性计算中有一定的适用性和通用性,同时也可将其作为原始参考应用于指定压气机级特性的推导和研究.     

变几何多级轴流压气机动态仿真模型的研究与应用

首先采用基于级平均直径上的一维流动逐级叠加法建立了变几何多级轴流压气机全工况性能预估模型,在此基础上,将压气机的级作为控制体,运用一维非稳态质量、动量和能量平衡微分方程来描述级出口截面处热力学参数动态特性,采用模块化方法建立各级集总参数模块,按照工质流程将各级的仿真模块连接起来即形成压气机通流部分机理性动态仿真模型.仿真试验表明:该仿真模型能够正确反映燃气轮机启动过程中与压气机有关的热力学参数变化过程,模型的动态响应特性与实际压气机热力参数的变化趋势基本一致.     

用于跨音速多级轴流压气机气动性能模拟的准一维程序

发展了一种能够较为准确预测跨音速多级轴流压气机气动性能的准一维数学模型。该模型基于欧拉方程外加源项的方法,可对多级轴流压气机的气动性能进行数值模拟。方程中的源项用于表示叶片、壁面摩擦以及流道面积变化对气流的影响,可以通过求解叶片排的进出口速度三角形求得。通过对跨音速压气机内部复杂的三维流动现象进行了简化,发展了合适的损失系数和落后角模型用来计算得到叶片排出口参数。对两种不同的多级跨音速压气机进行了数值模拟并与实验结果进行了对比,验证了本模型能够较为准确地模拟出跨音速轴流压气机的气动性能,但计算的精确度还需要根据不同的压气机类型对经验公式的系数进行优化。发展的模型根据压气机简单的几何尺寸就能对其气动性能做出较为准确的预测,这在压气机的预设计以及优化阶段有着重要的指导作用。     

流道粗糙度对离心式压气机效率影响的研究

本文针对涡轮增压器离心压气机流道粗糙度进行数值仿真计算,探究其对压气机效率损失的影响。研究结果表明:随着压气机流道粗糙度的增大,压气机的效率随之降低;在恒定转速下,随着压气机稳定流量的增加,流道粗糙度变化引起的效率衰减量逐渐增加;在恒定流量下,随着压气机转速的增加,流道粗糙度变化引起的效率损失衰减量逐渐减小;在不同工况下,叶轮表面粗糙度变化引起的效率损失量均大于压壳流道粗糙度变化引起的效率损失。     

Numerical Investigation of Base-Setting of Stator’s Stagger Angles for a 15-stage Axial-Flow Compressor简

A 15-stage axial-flow compressor utilized in steel industry was studied in this paper. All the stator＇s stagger an- gles of the compressor are variable to ensure the multistage compressor operate effectively within a wide range of flow rate and meanwhile satisfy the demand for sufficient pressure ratio, adiabatic efficiency and stall margin. Three in all different base-settings of stator＇s stagger angles were presented and commercial CFD soft-ware was applied to obtain the overall performance characteristics. The results showed that both of the optimized base-settings improved the performances both in summer and winter conditions, although the adiabatic efficiency was somewhat decreased. Taking incidence angle and stage loading into consideration, differences among the three cases were analyzed in detail. On the basis of numerical computations, the performance could be effectively improved through adjusting the base-setting of stator＇s stagger angles.     

Thermodynamic optimization for an open cycle of an externally fired micro gas turbine (EFmGT). Part 1: Thermodynamic modelling

The principle of optimally tuning the air flow rate and subsequent distribution of pressure drops is applied to optimize the performance of a thermodynamic model for an open regenerative cycle of an externally fired micro gas turbine power plant with pressure drop irreversibilities by using finite-time thermodynamics and considering the size constraints of the real plant. There are eight flow resistances encountered by the working fluid stream for the cycle model. Two of these, the friction through the blades and vanes of the compressor and the turbine, are related to the isentropic efficiencies. The remaining flow resistances are always present because of the changes in flow cross-section at the compressor inlet and outlet, the turbine inlet and outlet and the regenerator hot/cold-side inlet and outlet. These resistances associated with the flow through various cross-sectional areas are derived as functions of the compressor inlet relative pressure drop, and control the air flow rate and the net power output and thermal efficiency. The analytical formulae for the power output, efficiency and other coefficients are derived, which indicate that the thermodynamic performance for an open regenerative cycle of an externally fired micro gas turbine power plant can be optimized by adjusting the mass flow rate (or the distribution of pressure losses along the flow path). It is shown that there are optimal air mass flow rates (or the distribution of pressure losses along the flow path) which maximize the net power output.     

Solar heat pump drying and water heating in the tropics

In this study, the performance of a solar assisted heat pump dryer and water heater has been investigated. A simulation program has been developed. The predicted results are compared with those obtained from experiments under the meteorological conditions of Singapore. A coefficient of performance (COP) value of 7.0 for a compressor speed of 1800 rpm was observed. Maximum collector efficiencies of 0.86 and 0.7 have been found for evaporator–collector and air collector, respectively. A value of the specific moisture extraction rate (SMER) of 0.65 has been obtained for a load of 20 kg and a compressor speed of 1200 rpm. Results suggest that the total drying time of the product decreases with the increase in drying potential. Drying potential is directly proportional to the air flow rate, drying air temperature and inversely proportional to the air relative humidity. Three important parameters that affect the system performance are solar radiation, compressor speed and the total load placed in the drying chamber. Both SMER and COP decrease with increase in compressor speed.     

浅析9E燃气轮机20CB-1电磁阀故障造成排烟温度过高原因

介绍了9E燃气轮机由于防喘电磁阀20CB-1故障而造成排烟温度高的故障现象、查找故障的方法和产生故障的原因,提出了相应的对策措施建议,从而使防喘电磁阀长期稳定可靠运行,避免了类似故障在同类型的机组再次发生.     

Investigation of a centrifugal compressor and study of the area ratio and TIP clearance effects on performance

In this research, the centrifugal compressor of a turbocharger is investigated experimentally and numerically. Performance characteristics of the compressor were obtained experimentally by measurements of rotor speed and flow parameters at the inlet and outlet of the compressor. Three dimensional flow field in the impeller and dif- fuser was analyzed numerically using a full Navier-Stokes program with SST turbulence model. The performance characteristics of the compressor were obtained numerically, which were then compared with the experimental results. The comparison shows good agreement. Furthermore, the effect of area ratio and tip clearance on the performance parameters and flow field was stud- ied numerically. The impeller area ratio was changed by cutting the impeller exit axial width from an initial value of 4.1 mm to a final value of 5.1 mm, resulting in an area ratio from 0.792 to 0.965. For the rotor with exit axial width of 4.6 mm, performance was investigated for tip clearance of 0.0, 0.5 and 1.0 mm. Results of this simula- tion at design point showed that the compressor pressure ratio peaked at an area ratio of 0.792 while the effi- ciency peaked at a higher value of area ratio of 0.878. Also the increment of the tip clearance from 0 to 1 mm resulted in 20 percent efficiency decrease.     

压气机的湿压缩特性及计算模型初步研究

在大量分析国外有关的压气机通流部分喷水的资料基础上,根据已取得的初步实验结果,总结了喷水后压气机性能的主要特点及影响性能的关键因素,从理论上对这些特点进行了分析论证。最后根据“湿压缩”的特点,提出了一种计算模型。     

进口畸变下涡流发生器对压气机流场的影响

为研究进口总压畸变条件下涡流发生器对压气机流场的影响,建立单级轴流压气机模型,计算和分析了不同工况下的压气机内部流场.计算结果显示:在进口畸变条件下,压气机流场恶化,性能降低;使用涡流发生器后,可以有效改善静叶叶根附近的流场,控制叶片尾缘分离,降低沿叶高方向的压力波动,从而削弱进口畸变对效率的负面影响,改善出口压力场,...     

Part-load performance characteristics of a lean burn catalytic combustion gas turbine system

The purpose of this study is to compare the part-load performance of a lean burn catalytic combustion gas turbine (LBCCGT) system in three different control modes: varying fuel, bleeding off the fuel mixture flow after the compressor and varying rotational speed. The conversions of methane species for chemical process are considered. A 1D heterogeneous plug flow model was utilized to analyze the system performance. The actual turbomachinery components were designed and predicted performance maps were applied to system performance research. The part-load characteristics under three control strategies were numerically investigated. The main results show that: the combustor inlet temperature is a significant factor that can significantly affect the part-load characteristics of the LBCCGT system; the rotational speed control mode can provide the best performance characteristics for part-load operations; the operation range of the bleed off mode is narrower than that of the speed control mode and wider than that of the fuel only mode; with reduced power, methane does not achieve full conversion over the reactor at the fuel only control mode, which will not warrant stable operation of the turbine system; the thermal efficiency of the LBCCGT system at fuel only control strategy is higher than that at bleed off control strategy within the operation range.