Abstract
The uniform distribution and experimental design is employed to study the thermo-hydraulic characteristics of a heat exchanger, which consists of the rotor-assembled strands mounted in circular smooth tubes. The uniform distribution and experimental design parameters include multiple rotor parameters such as rotor diameters, rotor lead, and height of blade, with the aim of studying their influence on the PEC, that is, ([Formula: see text]), which stands for the heat transfer and friction characteristics. The best matching schemes of rotor-assembled strand, which significantly improves PEC to 2.01, are given by the regression analysis of uniform distribution and experimental design table. The single-factor experiments are performed to compare a tube installed with different kinds of rotor-assembled strands with a smooth tube without any strands when the Reynolds number changes between 20,000 and 60,000. The experimental result is in good agreement with the result obtained by the regression analysis of uniform distribution and experimental design. It is shown that the rotor diameters play important role in the heat transfer, and the optimal PEC value is obtained under the case that the rotor diameter is 21 mm. The rotor lead also contributes to the improvement of heat transfer and its optimal value is 700 mm in this study. The Nusselt number, friction factor and PEC increase with the increase in blade height. It shows that the uniform distribution and experimental design is an efficient method to find out the optimal parameters.
Highlights
Heat exchanger is the equipment to achieve heat exchange of cold and hot fluid in the engineering application, which is widely used in electric power, petrochemical, metallurgy, light industry, and other industries
It is of great significance to analyze the heat transfer enhancement regularity of heat exchanger caused by the rotor diameter, lead, blade height, and their interactions in depth
The formula that describes the relationship between rotor diameter, lead, blade height, their interactions, and performance evaluation criteria (PEC) is obtained by regression analysis
Summary
Heat exchanger is the equipment to achieve heat exchange of cold and hot fluid in the engineering application, which is widely used in electric power, petrochemical, metallurgy, light industry, and other industries. In order to meet the requirements of heat transfer, reduce the manufacturing costs, and save maintenance costs as much as possible, the transfer tube in the inserts, which has the advantages of enhanced heat. The structure of the insert has various forms such as winding filaments, helix, ties, and rotor.[1] Ai-Ping and Hong-Juan[2] studied the average surface heat transfer coefficient and fin efficiency in a spiral finned tube. The heat transfer enhancement and pressure drop of the helix in horizontal concentric sleeve were studied by Naphon.[4] Their results showed that the helix has significant effect on reinforcement of heat transfer, especially in the laminar flow area, but the helix reinforcement effect is weakened with the increase in Reynolds number. Pahlavan et al.[5] conducted studies of the heat transfer, resistance, and dirt in the helix and winding filaments, respectively. In contrast to the spiral spring and helix, the hydraulic turbine is a kind of new technology to strengthen the heat transfer of tube
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
