Dynamic Characteristics Analysis Of The Ship Cooling Water Piping System

Absract: The piping system is very important to the ship power system. It can not onlydeliver fluid and gas for the ship, but also influent the dynamic and noise characteristic of theship, including the safety and stealth of warship, and the comfort of private ship. Consequently,there is an significance of research on dynamic analysis of the ship piping system.This paper takes ship’s cooling piping system as example, and simplifies the virtual modal.This article takes the variation of siphonium pipe’s cross-section area which influencescalculation result significantly into consideration. In this article valves and flanges are simplifiedas lumped mass, supports are simplified as elastic restraint in transverse and vertical direction,pump and condenser are simplified as clamped boundary condition. And then analyzes the modalcharacteristics and dynamic response. Comparing the results with experiment data shows thevalidity and reliability of the method used to simplify the finite element modeling.This paper analyzes several types of excitation source and their exciting force characteristicsof ship’s fluid conveying piping system. Pressure pulsations and mechanical vibrations which aretransmitted to the piping system is the most important factor which causes pipe’s vibration. Thispaper analyzes the force of the piping system, and calculates the excitation force caused bypressure pulsation and velocity fluctuations, through Contrast, motivating force induced byvelocity fluctuations can be regarded as a steady force, which can be ignored during the dynamicresponse analysis. The exciting force caused by pulsating pressure is loaded to the finite elementmodel as the only excitation source. Comparing the calculated pipe displacement dynamicresponse spectrum with the measured velocity spectrum shows the trend curve and peak positionis consistent. Comparing the peak velocity value with the experimental value shows the largergap. It indicates that considering only the pressure pulsation as a single excitation source of thevibration characteristics of the ship piping system can result in similar trend, but to get accuratenumerical results needs further consideration to other incentive sources.On the basis of the finite element model, three optimization methods like pulsatingsuppressors, flexible pipes and changing supports’ spacing are used to get the damping effect infinite element method. Comparing damping effect, pulsating suppressors and flexible pipes forpiping system are discovered to be obvious, damping effect of changing supports’ spacing hasless impression on vibration characteristics of the piping system. At last, the appropriatedamping optimization experiments are conducted to prove the Validity of this conclusion.