离心压缩机圆形截面蜗壳内部三维流场的实验研究

利用五孔探针对离心压缩机蜗壳内部的三维流动进行了详细的测量,在此基础之上,着重对圆形截面偏心蜗壳内部三维流场的流动过程进行研究与分析,旨在为把握其三维流动的生成演化细节和积累流动图谱等基础性资料,为今后蜗壳设计与改良提供可靠数据并打下良好基础。     

离心泵侧壁式压水室的模态计算分析

基于有限元分析软件ANSYS对一种具有特殊结构形式的离心泵压水室进行了模态计算分析,获得了无预应力和有预应力两种状态下压水室的前6阶固有频率和模态振型。分析结果表明:侧壁式压水室的各阶固有频率均远离主要激励频率,可有效避免共振的发生;压水室的变形主要发生在进口法兰端和扩散段,可相应增加两处的刚度以优化压水室的振动特性;有预应力状态下压水室的各阶固有频率较无预应力状态下出现约1%的增幅,2种状态下压水室的变形方式基本一致。分析结果为带有侧壁式压水室离心泵的安全运行和结构优化提供了一定的理论指导。     

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     

双吸双流道泵固液两相流动特性分析

为研究双吸双流道泵的固液两相流动规律,本文基于CFD性能预测方法,计算泵在不同沙粒直径、不同沙粒浓度、不同流量工况的内部流动规律与外部特性曲线,并与单相流进行对比分析。研究结果表明:含沙多相流,流道中的压力梯度更大,压差分布更明显;流道内的脱流损失更严重,漩涡区域更明显,叶轮出口与蜗壳进口的动静耦合作用更剧烈;固相颗粒主要集中在叶轮的上下盖板处以及靠近蜗壳出口侧的流道区域;叶轮流道进口处的颗粒相对较少,出口处的颗粒相对较多;颗粒直径的变化对固相的离析作用明显,随着泥沙直径与流量的增大,泵的进出口总压差减小,随着泥沙浓度的增大,泵进出口总压差增大。     

TRT蜗壳稳态运行特性的数值模拟

通过有限元的方法,对大型TRT蜗壳式焊接机壳在热稳态运行条件下的温度场、应力场以及变形场的分布情况进行了数值模拟。计算结果表明,整个TRT蜗壳在热稳态运行条件下,机壳由于温度载荷的作用产生了热膨胀,机壳上的等效应力值均不大,大部分区域应力在100 MPa以下,在上机壳筋板附近,等效应力值比较集中,筋板上的等效应力值在70 MPa左右,最大值为117 MPa,出现在筋板的局部尖角处。整个机壳最大等效应力为168 MPa,远小于其屈服强度,因此满足强度要求。整体机壳的轴向收缩量较大,机壳在排气室与端板处收缩1.711 mm,变形并不大。因此,在稳态运行过程中,蜗壳的刚度足够。     

串列叶栅后焊接排气蜗壳改进设计

对组装式离心压缩机某模型级的实验装置进行了数值模拟。通过对模型级原结构及流场的分析,进行了多种焊接型式排气蜗壳方案的改进设计,并通过对比分析,得到比较理想的焊接排气蜗壳设计方案,实现级效率提高约4%。     

Application of New Type Pre-classification Hydrocyclone with Centrifugal Volute in Grinding Process

Hydrocyclone is widely used in closed-circuit grinding process. However, in the first classification operation of coarse particles with high pulp density, the shortcomings of traditional cyclone are that the grinding cycle load is much high, the apex of cyclone is easily to be blocked and classification efficiency is less. Specifically, the problems of traditional cyclone used in grinding process are as follows： （1） Mill utilization factor is low and its handling capacity is small; （2） Coarse particles mixing in cyclone overflow affects the following separation process and fine particles mixing in underflow causes over-grinding, which affects the total recovery rate of valuable minerals; （3） High grinding cycle load leads to large amount of high-density slurry pumping, which causes high energy consumption and severe wear of cyclones, pipelines and pumps. The applications of new type pre-classification hydrocyclone with centrifugal volute in the first classification process of iron mine mill are introduced in the paper. Pulp particles fed in the centrifugal volute are arranged in advance, so that coarse particles can be far away from the overflow pipe, which can reduce the short circuit current to avoid coarse particles entering overflow and improve classification efficiency and accuracy of cyclone. The strong points of the new cyclone in the coarse classification operation are as follows： （1） Finer overflow and less fine particles mixing in underflow improves classification efficiency more than 10%; （2） Lower ball mill load cycle improves ball capacity more than 10%; （3） Grinding energy consumption reduces by more than 20% and cyclone feed pump reduces energy consumption by more than 12%. In short, new type pre-classification cyclone with centrifugal volute solves the problems of fine particles mixing in underflow, high grinding cycle load and less classification efficiency in the coarse classification operation. Therefore, it has broad application prospects in ferrous metal and non-ferrous metal ore dressing plant.     

磁力消防泵蜗壳结构的流场特性

为了有效改善消防泵的输送特性及外特性(扬程、流量等特性),以提高消防泵的运行效率,文章基于磁力泵无接触传动的特点,将其作为消防泵蜗壳结构特性改进研究的基础,利用FLUENT软件对改进效果进行了比较研究。研究发现:从两种蜗壳喉部卸压区压力分布来看,矩形螺旋蜗壳的卸压效果要好,表现为梯度明显。环形蜗壳在隔舌处留有较大空间,导致了在此处的速度较大,而螺旋蜗壳则较好的控制了这点的分流。本研究为进一步提高磁力消防泵效率和蜗壳部分的优化改进奠定了基础。     

单级跨音速离心压缩机叶片扩压器和不同蜗壳形式耦合的内部流动数值研究

对单级跨音速离心压缩机具有对称和非对称两种形式的圆形截面蜗壳的内部流动进行数值研究, 分析蜗壳内部流动以及蜗壳与扩压器相互作用所导致的流动现象和不同工况条件下蜗壳进口周向流动的不均匀性以及两种蜗壳布置形式下各部件的流动损失.计算结果表明:在设计流量下和大流量下,对称蜗壳的蜗舌附近叶片扩压器通道中出现了回流,发生位置都在叶片扩压器叶片凸面;偏心蜗壳仅在大流量时出现回流现象,蜗舌附近区域内部流动情况略好于对称蜗壳.在非设计流量下,静止部件内部损失均大于设计流量,其中在大流量下尤为明显:扩压器内部损失在静止部件总损失中均占到80%以上,蜗壳内部损失小于20%;小流量下叶片扩压器内部损失所占比例小于大流量工况.     

Numerical prediction of 3-D periodic flow unsteadiness in a centrifugal pump under part-load condition

Numerical simulation and 3-D periodic flow unsteadiness analysis for a centrifugal pump with volute are carried out in whole flow passage, including the impeller with twisted blades, the volute and the side chamber channels under a part-load condition. The pressure fluctuation intensity coefficient （PFIC） based on the standard deviation method, the time-averaged velocity unsteadiness intensity coefficient （VUIC） and the time-averaged turbulence intensity coefficient （TIC） are defined by averaging the results at each grid node for an entire impeller revolution period. Therefore, the strength distributions of the periodic flow unsteadiness based on the unsteady Reynolds-averaged Navier-Stokes （URANS） equations can be analyzed directly and in detail. It is shown that under the 0.6Qd~. condition, the pressure fluctuation intensity is larger near the blade pressure side than near the suction side, and a high fluctuation intensity can be observed at the beginning section of the spiral of the volute. The flow velocity unsteadiness intensity is larger near the blade suction side than near the pressure side. A strong turbulence intensity can be found near the blade suction side, the impeller shroud side as well as in the side chamber. The leakage flow has a significant effect on the inflow of the impeller, and can increase both the flow velocity unsteadiness intensity and the turbulence intensity near the wall. The accumulative flow unstea- diness results of an impeller revolution can be an important aspect to be considered in the centrifugal pump optimum design for obtaining a more stable inner flow of the pump and reducing the flow-induced vibration and noise in certain components.