空调用贯流风机进气状态对其性能的影响分析

本文采用计算流体力学(CFD)的方法建立空调室内机流道的数值计算模型,定义了用于描述室内机贯流风机进气口气流方向的参数偏心度Φ.分析了室内机不同类型的前面板和换热器对贯流风机进气口流场状态速度分布,偏心度分布的影响,以及其与室内机性能的关系.为合理布置室内机前面板、换热器等结构,优化贯流风机进气口气流状态,提高贯流风机流量,降低贯流风机噪声提供参考.     

热交换器布置方式对家用空调器噪声影响的理论分析

从理论上分析了热交换器布置方式对家用分体式空调器室内机所用横流风机系统的流场和声场的影响，说明了圆弧形为理想的布置方式；并对三种具有不同热交换器布置方式的横流风机系统的流场进行了二维数值模拟，结果与理论分析相吻合，较好的预测了家用分体式空调的内部流场。     

空调贯流风机湍流流场的数值模拟

以某型号空调用贯流风机为研究对象,建立其整机二维全流场整机模型,采用数值模拟方法对其在设计工况下的内部湍流流场进行了数值模拟,着重分析了贯流风机速度场、压力场及重要湍流参数湍动能的分布规律,揭示了贯流风机内流场的基本特征。分析结论可为贯流风机的优化设计提供参考,对提高其整体性能具有工程应用价值。     

贯流风机流场模拟与性能分析

利用计算流体力学(CFD)软件STAR-CD对贯流风机内部气体流动进行了数值模拟,研究了贯流风机的流动状态和结构参数变化对其产生的影响,分析了蜗舌间隙、进口角、蜗壳间隙、蜗舌位置角、出口角变化与贯流风机进、出口流速间的关系,从中寻找出结构参数变化对贯流风机流场影响的规律。同时,还将模拟计算结果与试验结果进行了比较,比较结果表明数值模拟的结果与试验结果基本吻合。     

横流风机内部流动试验研究

利用激光多普勒测速（LDV）技术,测量并分析在不同叶轮直径和结构尺寸时,横流风机在稳定工况和失速工况下,风机内部流场的相似与差异,通过对几组试验数据的比较,对横流风机特有的偏心涡的成因进行了理论分析,并对偏心涡的主要参数特点作了深入的探讨,同时总结了偏心涡的位置随流量变化的规律。     

Performance of a cross-flow fan with various shapes of a rearguider and an exit duct

A cross-flow fan having forward curved blades relatively produces higher dynamic pressure at low rotating speed because a working fluid passes through an impeller blade twice. Most of this dynamic pressure is transferred to the static pressure in a rearguider and a stabilizer as a scroll in the centrifugal fan. The effect of a rearguider and a stabilizer on the performance of a cross-flow fan is higher than that of the impeller. Therefore, it should be considered how the shape of a rearguider and an exit duct affects on the performance and the flow fields. The purpose of this study is to investigate the reciprocal relation to the flow field and performance among the design parameters. Two-dimensional, unsteady governing equations are solved using FVM algorithm, sliding grid system and standard k - ɛ turbulence model. Verlocity profiles with various parameters are depicted. Furthermore, the meridional velocity profiles around the impeller are plotted at fixed rotating speed and design flow rate. This paper was presented at the 9^th Asian International Conference on Fluid Machinery (AICFM9), Jeju, Korea, October 16–19, 2007.     

Mean streamline analysis for performance prediction of cross-flow fans

This paper presents the mean streamline analysis using the empirical loss correlations for performance prediction of cross-flow fans. Comparison of overall performance predictions with test data of a cross-flow fan system with a simplified vortex wall scroll casing and with the published experimental characteristics for a cross-flow fan has been carried out to demonstrate the accuracy of the proposed method. Predicted performance curves by the present mean streamline analysis agree well with experimental data for two different cross-flow fans over the normal operating conditions. The prediction method presented herein can be used efficiently as a tool for the preliminary design and performance analysis of general-purpose cross-flow fans.     

贯流风机性能参数实验与扭曲角优化

介绍了一种自行研制的电壁炉用贯流风机性能参数检测台,详细描述了检测台中关键部件的实验测试原理,并对直叶片和扭曲叶片贯流风机在热风状态下的性能参数(出风口风速、风量和风机转速等)进行了对比实验研究,得出了扭曲角为60°的扭曲叶片贯流风机的性能明显优于直叶片贯流风机。同时对扭曲叶片贯流风机流场进行了数值模拟,并对扭曲角进行了优化。结果表明:数值计算和实验结果基本吻合,这两者的结合是研究贯流风机结构和改进其性能的有效手段。     

UNSTEADY FLOW ANALYSIS IN A CROSS-FLOW FAN WITH A CASING

ＵＮＳＴＥＡＤＹＦＬＯＷＡＮＡＬＹＳＩＳＩＮＡＣＲＯＳＳ－ＦＬＯＷＦＡＮＷＩＴＨＡＣＡＳＩＮＧＵＮＳＴＥＡＤＹＦＬＯＷＡＮＡＬＹＳＩＳＩＮＡＣＲＯＳＳ－ＦＬＯＷＦＡＮＷＩＴＨＡＣＡＳＩＮＧＣｈｅｎＣｉｃｈａｎｇ（ＪｉａｎｇｓｕＵｎｉｖｅｒｓｉｔｙｏｆ...     

多孔材料蜗舌对贯流风机的气动声学性能影响

在不改变蜗舌的几何外形与尺寸的情况下,使用4种不同的多孔材料制作蜗舌,得出某贯流风机蜗舌的4种替换方案.通过对其气动和声学性能的实验测试,比较了多孔材料制作的蜗舌对贯流风机的气动性能和噪声特性的影响.     

换热器结构对室内机风道系统流场特性影响的研究

建立了由贯流风机和换热器组成的空调室内机的三维物理模型,并通过Fluent计算软件对具有四种不同结构的换热器的空调室内机风道系统流场进行了模拟计算,分析了不同换热器结构的风道系统的静压以及速度分布,并统计了流经换热器的气流的分布。为改善空调室内机风道系统、提高空调舒适性提供理论的依据。     

贯流风机的性能预测/平均流线法

介绍了一种基于经验损失模型基础上的性能预测方法,即平均流线法.试验结果证明,在工程上,平均流线法在进行贯流风机性能预测可达到较为满意的结果.     

Effect of cross-flow velocity on flow and heat transfer characteristics of impinging jet with low jet-to-plate distance

An effect of cross-flow velocity on flow and heat transfer characteristics of impinging jet in the case of low jet-to-plate distance at H = 2D was experimentally and numerically investigated. In the experiments, the air jet from orifice impingement on the wall of wind tunnel while a cross-flow was simultaneously induced normal to the jet flow. The jet velocity was fixed while the cross-flow velocity was varied corresponding to velocity ratios (jet velocity/cross-flow velocity) VR = 3, 5 and 7. The temperature distribution on an impinged surface was visualized by using thermochromic liquid crystal sheet (TLCs), and Nusselt number distribution was evaluated by using image processing method. The flow pattern on impingement surface was visualized by using oil film technique. The numerical simulation was carried out for a better understanding of the jet flow in the cross-flow. The results show that Nusselt number peak shifts downstream and the Nusselt number peak increases with increasing cross-flow velocity.     

板式蒸发式冷凝器传热性能试验研究

搭建了板式蒸发式冷凝器传热性能试验平台,对影响板式蒸发式冷凝器传热性能的主要因素———喷淋水流量、风速、汽液流向以及工艺流体进出口位置进行试验研究。结果表明:空气与水并流时传热效果最好、逆流次之、错流最差;板内冷凝压力随冷却循环水喷淋密度、风速的增大而减小;在各自最佳风速,不同汽液流向操作下,蒸汽对角进出时的热流密度均比蒸汽同侧进出时大。     

车用加热器助燃风扇性能分析

通过对国产和德国同一类车用加热器助燃风扇的叶片结构、风扇特性、气体流动和比转速进行对比分析,反映出国产风扇在设计和工艺上的不足,有待于进一步的优化.     

高速列车牵引电机冷却风机风量实车测量方法研究

通过地面标定实验，对270km/h高速列车牵引电机冷却风机风量实车测量方法进行了研究，得到了皮托管动压及风机全压与流量的关系。研究结果表明所提出的皮托管流量测量法和风机全压流量测量法可用于实时检测列车运行过程中风机冷却风量。     

核电站EVR系统风机设计探讨

在核电站EVR（安全壳连续通风）系统中,由于腐蚀蒸汽的产生,因此限制了铝锌材料风机的应用,EVR风机就是在此条件下开发出来的。文中介绍了核电站EVR系统钢叶轮轴流式通风机的设计要求、产品结构和计算过程。经测试证明,该风机各项性能满足核电站使用要求,具有设计使用寿命长、效率高及启动时间短等特点。     

旋涡风机壳体在内流场作用下的动力响应

数值模拟了旋涡风机壳体在内流场作用下的动力响应。通过对燃料电池车上旋涡风机声振测试试验,数值模拟风机内部三维非定常流场,并对旋涡风机壳体进行动力响应计算。分析结果表明,旋涡风机在内流场作用下振动的激振频率与固有频率发生共振,造成风机结构振动向外辐射噪声,同时此方法能够较为准确地模拟壳体在内部流场激励下的动力响应。     

空调器室内机气动噪声模拟

采用数值模拟的方法对空调器室内机气动噪声进行了计算,分析了室内贯流风机蜗舌处的压力脉动,并通过Curle方程和快速傅里叶变换得到了蜗舌处旋转噪声频谱。通过对旋转噪声频谱的分析,证明了采用不等距叶轮可大大降低贯流风机基频处噪声,使基频的声能分布到较宽的频带范围内,并且可以使基频的峰值移到低频部分,从而使风机的噪声干扰能力大大降低。同时通过对各种不等距叶轮的旋转噪声频谱进行分析,提出了一种能够有效降低贯流风机旋转噪声的不等距叶轮结构。     

Experimental and numerical analysis on the effect of inlet distortion on the performance of a centrifugal fan with a mixing chamber

Inlet flow distortions, which are caused by fluid mixing, cause a significant deterioration in fan performance. An experimental test rig for an industrial fan with dual inlets and a mixing chamber was constructed. The flow fields in the mixing chamber of the fan were numerically investigated. Consequently, impact parameters, including the length of the mixing chamber (100, 200, and 300 mm) and the mass flow rate ratio (1 to 10), as well as their effects on fan performance, were discussed. A generalized formula considering the Reynolds number, hydraulic diameter, and mixing length was proposed to predict the pressure drop in dual inlets. Results show that the efficiency of and pressure in the fan decreased by 6.5% and 203 Pa, respectively, under mixing inlet condition. Optimum fan performance is achieved at a flow rate ratio of 5 under the same mass flow rate. The increase in the flow rate ratio kept the fan performance almost constant. At the design stage, fan performance and pressure decrease by an average of 2% and 70 Pa in increments of 100 mm mixing length, respectively. The results presented in this paper provide a basis in the design optimization of mixing structures.