Similarity theory and modeling. Similarity phenomena. The basic criteria of similarity in heat transfer, mass and momentum. Criterial equations. Dimensional analysis, π-theorem, Huntley method. The method of transfer equations to non-dimensional form. The method of similarity transformation. Simulation - types of models. Mathematical modeling, isomorphous equations. Hydrothermal analogy, electrothermal analogy. Physical modeling. Approximate modeling, partial and complete auto-similarity. Examples of modeling specific processes. Production of nitrogen oxides during combustion. Heat removal during cooling of the hot surface of the water jets. Cooling of steel in ladle. Solidification and cooling of steel during continuous casting. Cooling material during rolling. Heat losses in distribution networks.