Magnetohydrodynamic (MHD) Micropump

Magnetohydrodynamic (MHD) Micropump

There are two types of micropump, mechanical and non mechanical micropump. In mechanical micropump, moving parts is involved to create fluid flow. The principles of this pump use several phenomenon such us piezoelectric, electrostatic, Thermopneumatic, and magnetic which are used to drive membrane to generate pumping action.

In non mechanical micropump, there are no moving parts involved. One of non mechanical micropump is magnetohydrodynamic micropump. This pump uses Lorentz force to generate pumping action.

Figure 1 Right Hand Rule (source figure: http://en.wikipedia.org/wiki/Lorentz_force)

When current is applied in magnetic field, there will be a force which the direction is follow right hand rule. In figure, magnetic field is represented by B, current is represented by I, and Force is represented by F.

Figure 2. Simple MHD pump

Figure 2. describes how MHD principle is applied as micropump. Magnet results magnetic field from N pole to S pole. Electrical circuit is arranged like at the figure. When there is fluid in channel, current will occur from top to the bottom resulting electrical loop. Then, Magnetic field and current will generate Lorentz force and resulting fluid flows.

Fluid in MHD should be a conducting fluid. Pure water is not conducting fluid, thus it cannot be used to MHD pump. But, if water consist material such as NaCl or Iron, it will be ionic solution and becomes conducting fluid.

Due to its principle which is not involved moving part and can generate continuous flow, therefore Microhydrodynamic pump is very suitable is biological applications.