Design and technological optimization of rubber-reinforced thin-layer movable joints in the structure of a pipeline vibration-isolating compensator

Thin-layer rubber-metal elements have been widely used in various fields of technology, including helicopter construction, support parts for bridges, shock absorbers in industrial and civil construction. Their work reliability is determined by the design and technological performance features, which require experimental testing and parametric optimization. The article presents the samples and basic models testing results which were aimed at increasing the strength indicators stability of the adhesive ``rubber-metal'' joints and ensuring the failure-free operation of a rubber-metal product in the structure of a pipeline vibration-isolating compensator.

Chaotic Characteristic Analysis of Vibration Response of Pumping Station Pipeline Using Improved Variational Mode Decomposition Method

The measured vibrational responses of the pumping station pipeline in the irrigation site were chosen to confirm the chaotic characteristics of the pumping station pipeline vibration and to determine the vibrational excitation that makes it chaotic. First, the chaotic properties of the pipeline vibration responses were investigated using a saturation correlation dimension and the maximum Lyapunov exponent. The vibration excitation with chaotic features was obtained using an improved variational mode decomposition (IVMD) method to examine the multi-time-scale chaotic characteristics of the pipeline vibration responses. The results show that the vibrational responses of each measuring point of the pipeline under different operating conditions have clear chaotic characteristics, where the chaotic characteristics of the axial points and bifurcated pipe points are relatively strong. The vibration of the operating conditions and measurement points affected by the unit’s operation and flow state change is further complicated. The intrinsic mode function (IMF) produces a low-dimensional chaotic attractor after the IVMD disrupts the vibration response. Still, the vibration excitation of the remaining components on behalf of the units does not have chaotic properties, implying that water pulsation excitation makes the pumping station pipeline vibrations chaotic. The vibration excitation caused by the unit’s operation covers the chaotic characteristics of the pipeline vibration and increases its uncertainty. The outcomes of this study provide a theoretical basis for further exploration of the vibration characteristics of pumping station pipelines, and a new method of chaos analysis is proposed.

Design of a particle damper and experimental study on vibration damping of the pipeline

In this work, we designed a particle damper which can be conveniently clamped on to a pipeline without affecting the existing structure, showing a promising application in vibration reduction of real aircraft. Based on the designed particle damper, the impact of particle filling rate on the vibration reduction effect, the effect of EDEM simulation on the energy consumption of particles in the vibration process of the damper, and the result of actual vibration reduction test of particle damper installed on hydraulic pipeline were investigated. It is found that the vibration of the pipeline decreases first and then increases with the increase of particle filling rate. The particle filling rate corresponding to the maximum particle energy consumption rate is consistent with that of the minimum pipeline vibration acceleration during the test, that is, from 94.9% to 97.9%. The simulation results are in good agreement with the test results. Moreover, the vibration of the hydraulic pipeline and actual aircraft pipeline are both obviously suppressed after the installation of the particle damper. These results fully demonstrate the effectiveness and practicability of the aircraft pipeline particle damper.

Vibration characteristics of pressure pipelines at pumping stations and optimized design for vibration attenuation

To explore the effects of different pressure pipeline layouts on pumping station pipeline vibration, this study establishes an ALGOR numerical model for pipeline flow considering fluid–structure interactions. A data acquisition and signal processing vibration test system is used to obtain vibration signals and verify simulation results including pipeline fluid velocity, fluid pressure, and transient stress. Based on the flow's vibration excitation characteristics, we consider structural vibration reduction technology and propose an optimized design scheme. As an example, we apply this approach to a pressure pipeline at the Ningxia Yanhuanding Pumping Station Project. Results show strong vibrations at the water inlet, the junction between the branch and main pipes, and the water outlet, with even stronger vibration at the inlet than at the outlet. In the optimized design scheme, adjusting the distance between the branch pipes only weakly reduces flow-generated pipeline vibration; increasing the pipe diameter and changing the main pipe's relative orientation show stronger effects. Vibration reduction is optimized for a main pipe dip angle of 2–5° relative to the branch pipes, simultaneously decreasing pumping station energy loss. These results provide a theoretical and practical basis for optimal design of pressure pipelines at high-lift pumping stations. HIGHLIGHT This paper established fluid-structure interaction-based water flow ALGOR numerical model of pressure pipeline in pump station; meanwhile, DASP vibration test system is adopted to acquire the vibration signals to verify the simulation results, analyze the incentive characteristics of pressure pipeline flow form on pipeline vibration and put forward optimized design scheme.

Dynamic stability of submerged pipelines

The paper considers the dynamic stability of submerged pipelines with denudation and sagging depending on their stiffness and the river flow rate. The hydrodynamic force frequency and natural vibrations of the pipeline are calculated at the actual and critical length of the pipeline sagging. It is shown that the frequency of the external hydrodynamic force applied to the sagged pipeline with the length corresponding to the critical, coincides with the frequency of natural vibrations. It is found that the loss of stability of submerged pipelines occurs in the resonant region of the pipeline vibration due to the increased variable hydrodynamic force.

Cause analysis of pipeline vibration in natural gas station

Natural gas station is an important part of the whole natural gas pipeline transmission system, in which the pipeline vibration is a hidden danger that cannot be ignored for the safe operation of the station. In view of the severe vibration of the pipeline in a natural gas station of an enterprise, the vibration acceleration sensors are used to test the vibration of each measuring point under different working conditions, and then the three-dimensional finite element model of the pipeline is established by using numerical simulation software to study its structural characteristics and gas column characteristics. Through the analysis of field test results and simulation results, it is found that there are two main vibration frequencies in the pipeline: 116.75 Hz and 123.0 Hz. The former is caused by the resonance between the gas column frequency and the natural frequency in pipe B; The latter is due to the impact of the gas column force in pipe A on pipe B.

Comparative Study on Flow Characteristics of Pipeline System Based on CFD

Based on the CFD numerical simulation method, this paper established a pipeline model to study the internal flow characteristics of three different combinations of hot water pipeline systems and thus obtained the flow field information such as pressure, flow rate, and flow rate inside the pipeline. The study results showed that the smoother the pipeline transition, the smaller the velocity uniformity coefficient; the higher the uniformity of the flow field, the smaller the pressure and velocity fluctuations, the smaller the resulting pipeline vibration. Besides, the flow characteristics have been greatly improved.

Analysis and Research on Flow Characteristics of Hot Water Pipeline System

Based on the CFD numerical simulation method, a pipe model was established to study the internal flow characteristics of two different specifications of hot water pipe system, and the related information of the flow field was obtained, such as the internal pressure, flow velocity and flow rate. The results showed that the smoother the pipeline transition was, the smaller the velocity uniformity coefficient would be, and the higher flow field uniformity means the smaller pressure and velocity fluctuations. Therefore, the pipeline vibration will be smaller, and the flow characteristics are greatly improved.