text: A multiphase flow system is one characterized by the simultaneous presence of several phases, the two-phase system being the simplest case. The term ‘two-component’ is sometimes used to describe flows in which the phases consist of different chemical substances. However, since the same mathematics describes two-phase and two-component flows, the two expressions can be treated as synonymous.
  Analysis of multiphase systems can include consideration of multiphase flow and multiphase heat transfer. The former occurs only if all parts are at the same temperature, but interphase heat transfer also occurs when the temperatures of the individual phases are different.
  If different phases of the same pure substance are present in a multiphase system, interphase heat transfer will result in a change of phase, which is always accompanied by interphase mass transfer.