"Numerical analyses, LDV experiments and flow visualization on laminar round jet of the gas of different density discharging into stagnant air"

Abstract

In a High Temperature Gas-Cooled Reactor(HTGR), air ingress after pipe rupture accidents causes corrosion of the graphite structures in a pressure vessel. To prevent this phenomenon, injection of inert gas might be very effective. We have done the transient and steady numerical analyses on the code based on the SIM-PLEST algorithm to study the flow behavior and mass transfer. Experimentally we have measured the velocity fields by LDV and we have suceeded the flow visualization by using the smoke tracer of the joss sticks and a slit light.
As the result, the followings were obtained. The jet is accelerated by the gravity force. The velocity fields by the LDV experiments agree with those by the numerical calculations. And it becomes evidence by the flow visualization that the width of the jet decreases due to the acceleration of the jet and the jet entrains ambient air near the jet outlet.