COMSOL 6.4 - Connection Between Inner and Outer Film

Connection Between Inner and Outer Film

The flows in the inner and outer films are connected through the channels in the rings. The oil that enters the channel from the outer film has to emerge in the inner film, assuming no accumulation in the oil channel. This gives the required condition for connecting the flow across both channels. In addition, correction pressure term are needed to account for the centrifugal forces. This results into the following conditions:

Here, the subscript m denotes the channel number. It is assumed that the mass transport through the channel is instantaneous. The feed pressure Po,m can be determined iteratively to satisfy the flow balance. The flow rate at the inner film and outer film sides in the channel is determined by

Here, Li,m and Lo,m denote the outer edges of the ring hole in the inner and outer film respectively. nin and nout are the normals to the outer edges of the ring hole in the plane of the inner and outer films, respectively.