共查询到18条相似文献,搜索用时 203 毫秒
1.
2.
应用多体动力学分析方法及仿真技术研究了某汽车转向机构间隙运动副在转向过程中的碰撞接触特性.首先应用ADAMS软件创建了该车的仿真模型.由悬架系统、转向系统、行驶系统等系统纰成.其次研究了『H]隙运动副的碰撞接触特性,包括转向横拉杆与转向梯形臂之间的运动副及转向梯形臂与悬架之间的运动副.根据实际工作特征,前者运动副采用空间圆柱铰模型,后者运动副采用平面圆柱铰模型.最后对模型进行了仿真分析.仿真结果表明,转向过程中,两问隙运动副的碰撞接触力与间隙大小成非线性关系,多个运动副间隙共存状念下各间隙运动副的碰撞接触力发生变化.这些研究结果为转向机构零部件设计、动力学特性分析提供了更为准确的实验依据. 相似文献
3.
针对控压钻井过程中井下可能发生气侵的特殊工况,提出一种可在异常工况下估计井底压力,并借此判断异常工况的方法.首先,基于简化的漂移通量模型,在传统控压钻井水力学模型中添加气体膨胀项,建立控压钻井气液两相流模型;其次,将井下环空摩擦积分和井底气侵量视为未知参数,将井底流量视为未知状态,设计一种可对未知参数以及未知状态进行联合估计的自适应观测器,并以此为基础估计井底压力;最后,通过仿真实验验证所提方法的有效性.仿真结果表明,所建气液两相流模型可在井下发生气侵时模拟井底压力变化,且所提观测器能实时准确地跟踪井底流量及压力变化. 相似文献
4.
研究螺杆转子转动过程中的流场变化有助于对双螺杆泵运行参数的优化。采用计算流体力学(CFD)方法,对双螺杆泵流场进行三维瞬态动网格仿真分析。针对Ω形双螺杆泵,建立内流场数值模型,通过仿真得到一个转动周期内泵内压力分布,同时研究了不同粘度下泵外特性的变化规律。仿真结果表明,泵内压力由吸入端到排出端逐级增大,与容积腔推挤增压规律相吻合;在吸入端容积腔截面和螺杆啮合缝隙内均存在负压,且由于泄露的原因,密封腔两端的压力分布并非完全一致,存在轻微差异;流量随着压差的增大而呈近似线性下降趋势,粘度越大,流量受压差的影响就越小;泵效随压差的变化曲线呈抛物线形,达到峰值后先逐渐减小,最后趋于平稳。实验结果与仿真一致,证明了仿真方法的有效性。 相似文献
5.
火炮发射精度由射击密集度和射击准确度组成,身管振动影响火炮射击密集度和准确度.但影响身管振动的因素很多,一直来很难建立符合实际的振动模型,对火炮的射击精度进行准确分析.目前火炮发射精度分析时模型较简单,考虑因素较单一,特别是缺少多因素同时作用时火炮发射时的精度问题研究.为解决上述问题,建立了起落部分的虚拟样机模型,利用ADAMS动力学仿真软件综合分析了弹丸质心偏移量、高低机齿轮啮合间隙和衬瓦身管配合间隙三种因素耦合对炮口振动的影响.分析表明多因素对炮口振动存在耦合影响,为炮口振动特性的综合分析以及对接触间隙的优化控制提供了依据. 相似文献
6.
网络流量特征是分析和研究网络性能、规划网络建设的基础。由于自相似模型能够更加真实地描述网络传输的特性,通过生成自相似性的流量进行仿真研究。提出将业务源流量自相似性与网络传输的TCP协议相结合进行研究的方法,探讨影响自相似流量的因素,分析网络行为随参数变化的情况。仿真结果表明业务源流量的自相似与网络状态无关,而网络传输的TCP协议自适应改变网络状态,从而间接改变网络流量的自相似性,但并不能消除业务源流量的自相似性。 相似文献
7.
8.
9.
10.
11.
Tomasz Zawistowski Michał Kleiber 《Archives of Computational Methods in Engineering》2017,24(3):519-542
High pressure variable displacement axial piston pumps are subject to complex dynamic phenomena. Their analysis is difficult, additionally complicated by leakage of the working fluid. Analytically gap flow is calculated with the Reynolds equation which describes the pressure distribution in a thin lubricating layer. The paper presents various approaches to analyze gap flow both in traditional axial piston pump and novel type of hydraulic pump, designed at the Polish Gdansk Institute of Technology. Because of large aspect ratio between the height of the gap and the size of pump elements, the authors present the numerical simulation approach using a local model to define a lubrication gap, linked to a global model of a pump from which boundary conditions were imported. User defined functions implemented in Fluent and Excel were used to calculate the pressure and velocity fields and assess the fluid flow rate. 相似文献
12.
漏损管理中,为了取得更好的经济效益和控制效果,需要将减压阀配置在最优的位置及最优的开度.针对供水管网漏损管理问题,研究了减压阀优化配置问题,提出了减压阀的漏损管理优化控制数学模型,应用协同进化遗传算法,对算例管网进行了数值仿真,验证了方法的有效性. 相似文献
13.
深入研究了目前流体流场的数值仿真问题,由于流体流场中可能存在着马赫数变化很大的流动情形,通常的方法不能较好地计算出准确的结果,因此找出一种能计算任意马赫数流动的算法是非常必要的.使用了一种耦合压力与温度修正算法求解Navier-Stokes方程.是通过连续方程和能量方程推得压力修正值与温度修正值的方程,并将压力修正值方程与温度修正值方程联立求解,而其它求解变量采用分离式求解的思想,求解中对流项差分格式采用了AUSM 格式,并在低马赫数时进行了改进.通过对喷管和圆弧凸包的数值仿真,较好地反映出了流场中的激波现象,计算表明方法能适应任意马赫数范围的流体流动,并且具有一致的计算精度. 相似文献
14.
15.
Zhaoxia Yang 《Computers & Mathematics with Applications》2010,59(7):2168-2177
We propose a lattice Boltzmann algorithm for an average pressure boundary condition at outlets in pipe flow systems. The advantage of this boundary condition is that only the average pressure is used to recover the non-trivial flow fields. The asymptotic analysis shows that this algorithm works for general curved boundaries and renders a second order accurate velocity and a first order accurate pressure approximation of the incompressible Navier–Stokes solution. Here, we verify the accuracy by numerical simulations of a Poiseuille flow and a less symmetric flow with non-trivial pressure field in channels inclined with arbitrary angle, and flows in a pipe with three outlets. 相似文献
16.
Numerical analysis of the unsteady flow in the near-tongue region in a volute-type centrifugal pump for different operating points 总被引:7,自引:0,他引:7
An investigation is presented on the unsteady flow behaviour near the tongue region of a single-suction volute-type centrifugal pump with a specific speed of 0.47. For this study, the flow through the test pump, which was available at laboratory, was simulated by means of a commercial CFD software that solved the Navier-Stokes equations for three-dimensional unsteady flow (3D-URANS). A sensitivity analysis of the numerical model was performed in order to impose appropriate parameters regarding grid size, time step size and turbulence model. The predictions of the numerical model were contrasted with experimental results of both global (flow-head curve and static pressure distribution at volute front side) and unsteady variables (unsteady pressure distribution at the volute front side filtered at the blade-passing frequency). Once validated, the model was used to study the flow pulsations associated to the interaction between the impeller blades and the volute tongue as a function of the flow rate, for several flow rates ranging from 20% to 160% of the nominal flow rate. The study allowed relating the blade passage with the pulsations of pressure and tangential and radial velocity at a number of reference locations in the near-tongue region. The numerical model was also used to evaluate the evolution of the leakage flow between the impeller-tongue gap and of the flow exiting the impeller through some specific angular intervals, during one single-blade passage. 相似文献
17.
18.
研究某轴流压气机叶顶复杂流动问题,为深入了解压气机叶顶泄漏流流动机制和引发失速的机理,对一亚音速轴流压气机进行全工况数值仿真与试验测量。提出通过对比试验数据和分析泄漏流的流动特性,随着压气机负荷的提高,泄漏流方向的改变引起叶顶堵塞区增大,并诱发压气机失速。采用不同工况下叶顶流场进行仿真对比分析。仿真结果表明,泄漏流与主流相互作用形成泄漏涡,距前缘40%弦长范围内泄漏流影响泄漏涡形态变化,其余部分泄漏流主要通过周向输运低能流体进一步堵塞通道;叶顶压力分布是决定泄漏流方向的主要因素。 相似文献