Session: 30-12 Testing 2

Paper Number: 128951

128951 - Pulsations and Vibrations in the Discharge Piping of a Throttled Supercritical CO2 Turbine 

Choke nozzles present an economical option to control the expander downstream conditions in high-pressure, high-temperature CO2 loops. However, the expansion and high fluid momentum exiting the choke may induce instability causing the pulsating behavior and vibration of the loop due to fluid-structure interaction. The current study investigates the performance of conventional choke design utilizing CFD simulations to provide detailed insight into jet behavior and interaction with the wall. The analysis uses constant boundary conditions and doesn't account for any flow instability due to fluctuations and swirl velocities at the expander outlet. The CFD outcomes reveal the whirling motion of the jet after exiting the choke sticking to the pipe wall during the initial phase of jet formation. This may create an impingement effect inducing pipe vibration and cyclic loading on the surfaces directly in the way of the jet. The whirling motion dissipates with time with the jet tending to position at the lower part of the expansion pipe. The study concludes with the design and evaluation of a flow conditioner-type choke that redistributes and homogenizes flow downstream of the choke reducing the undesirable excitations and potentially the pipe vibrations. The solution was implemented, and the resulting pressure fluctuations and vibrations reduced greatly.

Presenting Author: Jason Wilkes Southwest Research Institute

Presenting Author Biography: Will provide at conf.

Authors:

Jason Wilkes Southwest Research Institute
Abhay Patil Southwest Research institute
Jon Bygrave Hanwha Power Systems