12/1/2010 Colloquium - Yoichiro Matsumoto

Yoichiro Matsumoto University of Tokyo

Event Info

Title:  Multi-scale Analysis on Cavitation Damage and its Mitigation for the Spallation Neutron Source

Date: Dec 1, 2010
Location: 3105 Etcheverry Hall
Time: 4-5pm

Abstract

The Spallation Neutron Source has been constructed in which liquid mercury is used as a target of proton beam. When pressure waves caused by thermal expansion of liquid mercury hit a wall, cavitation occurs and erodes the wall, which is made of thin stainless steel. To mitigate the cavitation damage, a method of introducing micro gas bubbles into liquid mercury has been proposed so that the bubbles absorb the thermal expansion of liquid mercury and attenuate the pressure waves. These complex processes were investigated numerically, using the Euler-Lagrange method for coupling the liquid metal and gas bubbles. To consider the nonlinear oscillation of bubble and the heat transfer through the bubble interface, we employed the bubble dynamics equation for compressible liquid with an assumption of spherical bubbles and solved the mass, momentum and energy conservation equations for gas inside each bubble with a moving coordinate system. Calculations show that the pressure wave due to the nuclear spallation is well attenuated and the cavitation is suppressed at the wall by the introduction of micro bubbles in mercury.

Speaker Biography

Professor Yoichiro Matsumoto received his Bachelor's (1972), Master's (1974), and Doctoral degrees (1977) in mechanical engineering from the University of Tokyo. He became a full professor in the University of Tokyo's Department of Mechanical Engineering in 1992. He is now the Managing Director and Executive Vice President at The University of Tokyo.

His previous appointments included various positions such as
Vice President, Dean of the School of Engineering,The University of Tokyo,
President of Japan Society of Fluid Mechanics
President of the Visualization Society of Japan
President of the Japan Society of Mechanical Engineers

He is a researcher with numerous awards such as the
Calvin W. Rice Lecture Award from American Society of Mechanical Engineers Japan Society Mechanical Engineering (JSME)

Medals for Outstanding Papers
Computational Mechanics Award from JSME
Fluids Engineering Award from JSME
JACM Award for Computational Mechanics
APACM Award for Computational Mechanics

He served as editor and editorial board member for several journals. He is an expert in the field of fluid engineering, molecular dynamics, rarefied gas dynamics and other areas of mechanical engineering.