Development of Compensators to Improve Vibration Isolation of Equipment of Thermal Plants through Pipelines and the Influence of Liquid Flow on the Effectiveness of Vibration-Isolating Compensators

Abstract

The results of experimental studies on the creation of highly efficient designs of vibration-isolating compensators for pipelines with liquid are considered. It is noted that the only way to evaluate the effectiveness of various compensators in reducing vibration at different frequencies currently is to compare their transient vibration stiffness or transient mechanical impedance, which were measured on special stands at a given frequency. The stiffness of the compensator increases significantly with increasing frequency vibrations. Hazardous frequencies may vary between piping systems. For this reason, it is impossible to set an integral criterion for the effectiveness of a vibration-isolating compensator, similar to static stiffness. The results of measurements carried out on a special stand on the transitional vibration stiffness of a new design compensator with thin-layer rubber-metal elements (TRME) are presented. The rigidity decreased by 10 or 100 times or more in the frequency range from 50 to 800 Hz relative to the rigidity of a serial compensator based on rubber cord casing (RCC), including in the presence of water inside it. It has been experimentally shown that the vibration-isolating ability of the same compensator as part of a pipeline system, determined by the value of the dynamic force transmitted by the compensator to the pipeline from the pump, significantly depends on the presence of water in them and its flow, which is not taken into account in known methods. The results of testing compensators with RCC and TRME with a bore diameter of 80 mm as part of a stand with a ring pipeline system, a pump, systems for monitoring the flow of the working fluid, vibrations, pressure pulsations, and dynamic (vibration) forces transmitted by the compensators to the pipeline are presented. In a stand with pipelines, the efficiency of vibration-isolating compensators with TRME is still 10 and 100 times higher than compensators with RCC in the absence of water and decreases by an order of magnitude in the presence of water without its flow when the pump is vibrated by a vibrator. Efficiency decreases even further if water flows through expansion joints and pipelines while the pump is running.