The heat transfer and analysis on laser beam, evaporator coils, shell-and-tube condenser, two phase flow, nanofluids, complex fluids, and on phase change are significant issues in a design of wide range of industrial processes and devices. The most common class of multiphase flows are two-phase flows. A gas-liquid flow is probably the most important form of multiphase flow, and is found widely in a whole range of industrial applications. These include pipeline systems for the transport of oil-gas mixtures, evaporators, boilers, condensers, submerged combustion systems, sewerage treatment plants, air-conditioning and refrigeration plants, and cryogenic plants. Gas-liquid systems are also important in the meteorology and in other natural phenomena. Flows of solids suspended in gases are important in pneumatic conveying and in pulverized fuel combustion. Fluidized beds may also be regarded as a form of gas-solid flow. Liquid-liquid flows are the flow of oil-water mixtures in pipelines and in liquid-liquid solvent extraction mass transfer systems. The most important application of liquid-solid flow is in the hydraulic conveying of solid materials. Liquid-solid suspensions also occur in crystallization systems, and in hydro-cyclones. Historically, probably the most commonly studied cases of two-phase flow are in large-scale power systems. Coal and gas-fired power stations used very large boilers to produce steam for use in turbines.Two Phase Flow, Phase Change and Numerical Modeling covers mainly numerical modeling of heat transfer, two phase flow, nanofluids, and phase change.