Heat transfer coefficient in a liquid under conditions of regular thermal regime
DOI:
https://doi.org/10.46299/j.isjea.20250402.09Keywords:
experimental study, non-stationary heat transfer, regular thermal regime, cooling (heating) rate, complex body, experimental fluid, convection, heat transfer coefficient, coefficient of non-uniform temperature distribution, non-stationary methodsAbstract
An experimental study of the heat exchange process during forced convection of a sugar solution under conditions of its heating (cooling) was conducted. The goal of the study was formulated, which involves: establishing the possibility of the existence of a regular thermal regime during cooling (heating) in a "complex body" under conditions of forced convection of a sugar solution in a cylindrical thin-walled metal vessel; using methods of a regular thermal regime to determine the intensity of heat exchange between a cylindrical metal wall and the test liquid. It was experimentally established that during the time interval in which the cooling (heating) of the sugar solution is studied, a regular thermal regime is realized. During the studied stage of the regular thermal regime, the cooling (heating) rate of the test liquid remains unchanged and does not depend on time. The average volumetric temperature of the "complex body" differs from the average volumetric temperature of the test liquid by 0.01÷0.03ºС. The heat transfer coefficient between the inner surface of the metal wall of a cylindrical vessel and the test liquid is recommended to be determined taking into account the methods of regular thermal regime, i.e. the rate of cooling (heating) of the test liquid, the coefficient of uneven temperature distribution. Non-stationary methods allow for a large number of measurements of heterogeneous data simultaneously, require a smaller number of measuring instruments and are characterized by a simpler organization of the test. It has been established that the values of heat transfer coefficients determined by the methods of regular thermal regime, i.e. by the methods of non-stationary heat exchange, and by the well-known computational and experimental method - the method of processing the results of stationary heat exchange, have a discrepancy between themselves, which does not exceed 15% during heating, and 20% during cooling.References
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Copyright (c) 2025 Olha Vlasenko, Stanislav Tkachenko, Oleksandr Nedbailo, Oleksandr Moshkov, Igor Melnichenko
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