Numerical simulation of heat exchanger operation

Abstract

Abstract. Numerical simulations have opened wide field of possible applications and opportunities to be used not only in science but also in the industry. With new developed numerical methods we can not only describe existing systems, but we can also predict possible behaviour or possible state of inspected system. This article deals with numerical simulation of proposed heat exchanger for hot air engine and with simulation of its possible states and behaviour with certain conditions. Heat source for hot air engineCogeneration unit with hot air engine should be used as an independent source of electrical and heat energy for the household to ensure an efficient energy supply with respect to high reliability. The source of heat is determined by the furnace for burning biomass, in form of a wood pieces, or pellets. Transport energy from the combustion of biomass to a working fluid in hot air engine is providing a heat exchanger connected to that source. In the design of the heat exchanger were taken into account all the conditions imposed on the heat exchanger and the desired properties. Most often the investigation of the heat transfer is the exchanger heat surface [1,2]. From this are derived all other parameters, external dimensions, connection dimensions, such as flanges, pipe connecting dimensions, mounting flange dimensions consoles supporting structures. Draft of heat exchanger for hot-air engine had to take into account a wide range of specifications and operating conditions. We have established basic dimensions using the criterion equations. To determine the boundary conditions have been transferred several measurements that confirm and specify the chosen boundary conditions. The basic schema of our proposed micro cogeneration unit is in the Figure 1.