压裂工况下高压管汇的振动特性分析

Analysis of Vibration Characteristics of High-Pressure Manifold During Fracturing

压裂车泵头体里面的柱塞泵以及连杆会产生较大振动,与泵头体相接的高压管汇在工作时会产生共振等危险。对于高压管汇流固耦合分析和改进安装约束方式综合考量的研究鲜有涉及,且在固有频率附近的响应情形尚不明确。为此,基于空挡位和单向流固耦合的模态分析方法,对比分析高压管汇的固有频率和振型,并对工况丁进行谐响应分析,揭示了改进约束方式对提高固有频率的影响规律。研究结果表明:无论是否增加固定约束,在流固耦合模态下比在空模态下的固有频率均要高2%~6%;改进约束方式后管汇的前3阶固有频率是改进前的2~3倍;管汇在改进前主要在中间直管段的上下、前后弯曲摆动,改进后变为上下、左右摆动,且管汇振动主要集中在中间直管段;在X方向上的位移、加速度、应力和应变谐响应峰值均比在Y和Z方向上的要高。研究结果可为高压管汇的设计以及增加固定约束的方式提供理论依据。

The plunger pump and connecting rod in the pump head body of fracturing trucks may vibrate greatly,and thus,the high-pressure manifold connected with the pump head body may resonate during operations.The fluid-structure coupling of high-pressure manifolds and the optimization of the installation constraints have rarely been studied,and the responses near the natural frequency are still unclear.Through modal analysis based on neutral position and unidirectional fluid-structure coupling,the natural frequency and vibration modes of the high-pressure manifold were analyzed,and the harmonic response analysis was carried out for the condition D to reveal the influences of the improved constraint mode on increasing natural frequency.The results show that the natural frequency of the fluid-structure coupling mode is 2%~6%higher than that of the empty mode,regardless of extra fixed constraints.The first three natural frequencies of the manifold after the constraint optimization are 2 to 3 times of those before optimization.Before optimization,the manifold is mainly seen with flexural vibration in the vertical and axial directions of the middle straight section.After optimization,the vibration changes to the vertical and horizontal directions and is still concentrated in the middle straight section.The harmonic response peaks of displacement,acceleration,stress and strain in the X direction are all higher than those in the Y and Z directions.The research conclusions provide a theoretical basis for the design of high-pressure manifolds and for placing extra fixed constraints.