An electro-conjugation fluid (ECF) is a kind of dielectric liquid, which generates a powerful flow when high DC voltage is applied with tiny electrodes. This study deals with the derivation of the governing equations for electro-conjugate fluid flow based on the Korteweg-Helmholtz (KH) equation which represents the force in dielectric liquid subjected to high DC voltage. The governing equations consist of the Gauss's law, charge conservation with charge recombination, the KH equation, the continuity equation and the incompressible Navier-Stokes equations. The KH equation consists of coulomb force, dielectric constant gradient force and electrostriction force. The governing equation gives the distribution of electric field, charge density and flow velocity. In this study, direct numerical simulation (DNS) is used in order to get these distribution at arbitrary time. Successive over-relaxation (SOR) method is used in analyzing Gauss's law and constrained interpolation pseudo-particle (CIP) method is used in analyzing charge conservation with charge recombination. The third order Runge-Kutta method and conservative second-order-accurate finite difference method is used in analyzing the Navier-Stokes equations with the KH equation. This study also deals with the measurement of ECF ow generated with a symmetrical pole electrodes pair which are made of 0.3 mm diameter piano wire. Working fluid is FF-1EHA2 which is an ECF family. The flow is observed from the both electrodes, i.e., the flow collides in between the electrodes. The governing equation successfully calculates mean flow velocity in between the collector pole electrode and the colliding region by the numerical simulation.
An electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a flow (ECF flow) when subjected to high
DC voltage. Since it only requires a tiny electrode pair in micrometer size in order to generate the ECF flow, the ECF is
a promising micro fluid pressure source. This study proposes a novel micro robot hand using the ECF. The robot hand is
mainly composed of five flexible fingers and an ECF flow generator. The flexible finger is made of silicone rubber
having several chambers in series along its axis. When the chambers are depressurized, the chambers deflate resulting in
making the actuator bend. On the other hand, the ECF flow generator has a needle-ring electrode pair inside. When
putting the ECF flow generator into the ECF and applying voltage of 6.0 kV to the electrode pair, we can obtain the
pressure of 33.1 kPa. Using the components mentioned above, we developed the ECF robot hand. The height, the width
and the mass of the robot hand are 45 mm, 40 mm and 5.2 g, respectively. Since the actuator is flexible, the robot hand
can grasp various objects with various shapes without complex controller.