Solution of the conjugate heat exchange problem for conical heat exchangers

RELEVANCE The article is devoted to the development of new designs of heat exchangers and evaluating the efficiency of their operation. According to the authors, currently of particular interest are conical heat exchangers of the "pipe-in-pipe" type, so the object of research in this paper is a heat exchanger in the form of a truncated cone based on a spring-twisted channel. The introduction of the proposed heat exchange elements and apparatuses into the industry requires additional research.  To assess the effectiveness of the application of the considered TA, it is proposed to evaluate its performance in comparison with conical and cylindrical TA based on a smooth-walled pipe. Due to this, two hypotheses will be tested at once: the use of a conical coil heat exchanger is more efficient than a cylindrical one, and the replacement of a smooth-walled pipe with a spring-twisted channel increases the efficiency of the heat exchanger.OBJECT.  The aim of the research is to develop a method for setting and solving the conjugate heat exchange problem for a heat exchanger in the form of a truncated cone with a heat exchange element in the form of a spring-twisted channel, analyze the results obtained and evaluate the efficiency in comparison with conical and cylindrical heat exchangers based on smooth-walled heat exchange elements. METHODS. For the numerical solution of the conjugate heat transfer problem, the FEM implemented by means of Ansys was used Fluent. RESULTS. The main results consist in the fact that the authors developed a model and algorithm for calculating conical coil heat exchangers of the pipe-in-pipe type, implemented in the Ansys program, and determined the thermal and hydrodynamic parameters of coil devices. A comparison of coil heat exchangers was also made: a conical one based on a spring-twisted channel with a conical one and a cylindrical one with a smooth-walled heat exchange element. The calculation results showed that replacing a smooth-walled pipe with a spring-wound channel significantly increases the efficiency of heat exchange equipment. CONCLUSION. The significance of the obtained results lies in the possibility of using modern, more efficient and compact heat exchange equipment for technological needs and in the justification of this choice. Thus, with equal initial data, conical heat exchangers are more efficient than cylindrical ones with a heat exchange element in the form of a smooth tube, since they need a smaller heat exchange surface to achieve the necessary thermal and hydrodynamic parameters. The results of calculations prove the prospects of using a conical TA based on a spring-twisted channel and show the need for further study of the influence of the geometric characteristics of both the coil itself and the heat exchange element on the thermal and hydrodynamic characteristics of the proposed HE.

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