Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 07, 2019 - November 08, 2019
The purpose of this study is the development of an elastic sensor for measuring wall shear stress induced by flow water. We used a flexible sensor by MCF Rubber. MCF is the abbreviation for magnetic compound fluid. MCF Rubber is composed of NR-latex, nickel powder, and magnetic fluid. These materials are mixed, then polymerized with electric heat. The MCF Rubber can measure the force normal to rubber sensor and the shearing force acting on the rubber since the MCF rubber is conductive rubber. The magnitude of the force measured with the change of electric conductivity of MCF Rubber. The change of electric conductivity causes when the deformation of rubber by some time force acting on the MCF rubber. For the consideration of shear stress measurement with MCF Rubber, we used mechanism of a rotational viscometer. Rotational viscometer consists with a rotor rotates by a motor, and the rotor makes a flow in circular container. The wall shear stress can be changed with a rotational velocity of rotor. The strength of wall shear stress can be defined as σ=3τ/2πR3 on Japanese Industrial Standard (JIS). Here, τ is the torque acting on the motor shaft, and R is the radius of rotor. So, the torque converter is installed between the motor and rotor to measure the torque. Six type rotational velocity ranging from 100 to 600 revolution per minute (rpm) to understand the characteristics of MCF Rubber sensor for the wall shear stress measurement. The result shows that the MCF Rubber can measure the change of wall shear stress under the unsteady flow condition.
