The performance of a Surface Scraped Heat Exchanger is investigated by numerical modeling
The performance of a Surface Scraped Heat Exchanger is investigated in this paper by numerical modeling. This type of heat exchanger is used for heat transfer of highly viscous fluids in many industries. The simulated heat exchanger comprises a stator and a rotor on which two blades are designed to blend the fluid at a constant speed. The fluid enters the heat exchanger steadily with constant mass flow rate and temperature and then cools down. The effects of three key parameters of rotor speed, flow rate, and the heat flux imposed on the casing, on the outlet temperature and the convection heat transfer coefficient are examined. Finally, the values of these parameters are optimized to maximize the convection heat transfer coefficient and minimize the outlet temperature. The results are summarized as follows:
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Increasing the rotor speed has favorable and unfavorable effects on the convection heat transfer coefficient and the outlet temperature.
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At low and middle levels of mass flow rate, increasing its value raises the convection heat transfer coefficient, but this also causes the unfavorable increase in the outlet temperature. Such a trend is observed in a high level of mass flow rate but in the inverse direction.
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The outlet temperature of the heat exchanger is least sensitive to the rotor speed and is most sensitive to the mass flow rate.
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Maximizing the convection heat transfer coefficient and minimizing the outlet temperature are conflicting objectives, thus the results of optimization are provided as a set of non-dominated optimal solutions.
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The convection heat transfer coefficient enhances by 380.64% along the Pareto front, while the outlet temperature enhances by 4.86%, which shows that the convection heat transfer coefficient highly depends on the selection of optimal points.