共查询到20条相似文献,搜索用时 140 毫秒
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采用两类相对流面的三元流动理论,即准三元流动理论,求解出离心通风机中叶轮,蜗壳等主要元件流道中速度分布的规律,建立起依赖于此速度分布的损失计算公式。考虑各项损失之间的相互关联和影响,建立起一个包含26个系数的风机整机损失数学模型,利用已有的后向离心通风机的试验数据,采用最优化的方法确定损失模型中的有关系数。通过试验检验了此模型的可靠性。 相似文献
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叶片的结构形式对离心通风机运行中的能量利用率具有重要的影响,采用速度分步法对叶片的结构形式进行优化设计,并对优化后的通风机性能进行分析。结果表明,采用速度分步法优化的叶片中以模型C的通风机性能最佳,其在减小通风机能量损失的同时,可提高通风机在额定工况及小流量工况下的性能。 相似文献
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为提高空气净化器中离心风机的风量,提出了一种基于Kriging近似模型和遗传算法的优化方法,采用正交试验的设计方法对蜗壳的出口扩张角θ、蜗舌半径r、蜗舌间隙t进行25组方案设计,并采用ANSYS FLUENT对25组蜗壳方案进行定常数值模拟,选取风机系统的风量作为优化设计目标,建立了风量与蜗壳的3个参数之间的Kriging近似模型,并用遗传算法对近似模型进行寻优,得到最优的蜗壳参数。通过对优化后的蜗壳进行仿真实验,风量提高了19.683%,同时对比优化前后的风机内部速度、总压等参数的分布,优化后的蜗壳内部速度分布更加合理,在蜗舌处的流动损失较小。提出的蜗壳优化方法对提高离心通风机性能提供了有效参考。 相似文献
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介绍了筒形离心通风机的特点,在一定的假设条件下得到了气体流动速度的计算公式,应用此公式计算了结果,经试验满足设计要求。 相似文献
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基于通风机整体运行效率不高的问题,采用速度分布法及载荷分布法两种设计方法对离心通风机的叶片结构进行优化设计,并采用有限元仿真的形式对优化后的通风机性能进行仿真分析.结果 表明,由速度分布法设计的叶片结构对通风机的运行效率及安全性能具有较大的提升,可作为离心通风机优化设计的首选方法. 相似文献
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参照轴流压气机动叶尾迹衰减规律,利用流动损失系数代替叶栅阻力系数,给出了离心叶轮出口粘性尾迹速度亏缺值及其宽度的计算方法。基于薄机翼理论,每个叶片用一组连续分布涡来代替,把环形叶栅片模化成在圆周上连续分布涡组的等分排列,建立了在离心叶轮粘性尾迹作用下扩压器叶片上不稳定力计算式。在此基础上对离心压缩机气动噪声进行了理论计算。并与实测值进行了比较,二者吻合较好。 相似文献
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离心通风机气动略图数据库的建立秦国良张孝生(西安交通大学)一、前言随着计算机应用的普及,通风机设计中应用计算机辅助设计技术越来越迫切,通风机设计系统的建立势在必行。离心通风机设计中,需检索大量已有模型机数据,需查阅、利用大量的图表及经验数据,因此,在... 相似文献
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Numerical simulation and analysis of flow characteristics in the front chamber of a centrifugal pump
Yang Wu Xiaoping Chen Hua-Shu Dou Lulu Zheng Zuchao Zhu Baoling Cui Boo Cheong Khoo 《Journal of Mechanical Science and Technology》2017,31(11):5131-5140
We performed numerical simulations to study the flow characteristic in a centrifugal pump based on the RANS equations and the RNG k-ε turbulent model. The flow field, including the front and back pump chambers, the impeller wear-ring, the impeller passage, the volute casing, the inlet section and outlet section was calculated to obtain accurate numerical results of fluid flow in a centrifugal pump. The flow characteristic was studied from the internal flow structure in pump chambers, the radial velocity at impeller outlet as well as the pressure inside of the pump, the circumferential velocity and the radial velocity in front pump chamber. The variation of flow parameters in internal flow versus flow rate in the centrifugal pump was analyzed. The results show that the overall performance of the pump is in good agreement with the experimental data. The simulation results show that the distribution of flow field in the front pump chamber is axial asymmetry. The energy dissipation at the impeller outlet is larger than other areas. The distribution of the circumferential velocity and that of radial velocity are similar along the axial direction in the front pump chamber, but the distribution of flow is different along the circumferential and the radial directions. It was also found that the vorticity is large at the impeller inlet compared with other areas. 相似文献
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基于熵产的侧流道泵流动损失特性研究 总被引:1,自引:0,他引:1
侧流道泵是一种介于容积式泵和离心泵之间的径向式叶片泵。泵内流体以螺旋轨迹方式在叶轮和侧流道中反复运动,整个运动是一种典型的全三维、高湍流强度、空间非对称的湍流流动,因此不可避免地产生较大的流动损失。利用热力学第二定律,基于熵产的流动损失分析方法对一种单级侧流道泵模型湍流流动损失进行研究,主要通过理论和数值计算求解湍流流动过程中增加的熵产,定性分析侧流道泵流动损失出现的位置及分布特点。结果表明,侧流道泵内部流动损失主要与湍流流动增加的熵产有关,而热量交换产生的熵产相对较小,在侧流道泵的损失研究中可以忽略;叶轮流道和侧流道内的湍动耗散率均远远大于直接耗散率;叶轮流道内的损失主要出现在叶轮内缘至0.4 r处,在侧流道内,流动损失主要出现在流道进口、流道中间靠近内缘部分以及出口附近。 相似文献
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This work developed improved slip factor model and correction method to predict flow through impeller in forward-curved centrifugal
fan. Both steady and unsteady three-dimensional CFD analyses were performed to validate the slip factor model and the correction
method. The results show that the improved slip factor model presented in this paper could provide more accurate predictions
for forward-curved centrifugal impeller than the other slip factor models since the present model takes into account the effect
of blade curvature. The correction method is provided to predict mass-averaged absolute circumferential velocity at the exit
of impeller by taking account of blockage effects induced by the large-scale backflow near the front plate and flow separation
within blade passage. The comparison with CFD results also shows that the improved slip factor model coupled with the present
correction method provides accurate predictions for mass-averaged absolute circumferential velocity at the exit of impeller
near and above the flow rate of peak total pressure coefficient. 相似文献
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Measurements have been made in an automotive HVAC blower for two different centrifugal fans. This work is directed at improving the performance of a conventional forward-curved centrifugal fan for a given small blower casing. Mean velocities and pressure have been measured using a miniature five-hole probe and a pressure scanning unit connected to an online data acquisition system. First, we obtained the fan performance curves versus flow rates showing a significant attenuation of unstable nature achieved with the new fan rotor in the surging operation range. Second, aerodynamic characterizations were carried out by investigating the velocity and pressure fields in the casing flow passage for different fan operating conditions. The measurements showed that performance coefficients are strongly influenced by flow characteristics at the throat region. The main flow features were common in both fans, but improved performance is achieved with the new fan rotor, particularly in lower flow rate regions. Based on the measured results, design improvements were carried out in an acceptable operation range, which gave considerable insight into what features of flow behavior were most important. 相似文献