Muna S. Kassim*, Fouad A. Salah and Ahmed O. Samarmad Pages 162 - 171 ( 10 )
Objective: Experimental and numerical investigation has been performed in this work to study the enhancement of heat transfer coefficient of TiO2/water nanofluid in spiral fluted tube equipped with twisted tape.Method: The performance of spiral fluted tube equipped with twisted tape heat exchanger with and without nanofluid was investigated experimentally. The concentration of nanofluid was varied from 0.08 to 0.3% while the twisted ratio (y/w) of twisted tape was kept constant at 4.0. Steam was used as a heating source where constant wall temperature condition (110 °C) was achieved. The experiments were performed in turbulent regime (Reynolds number spanned 7000 ≤ Re ≤ 15000). Results: Experimental results reveal that the use of spiral fluted tube equipped with twisted tape without nanofluid leads to an increase in 37% to 43% in heat transfer coefficient compared with smooth tube. The maximum increase in heat transfer coefficient occurs with nanofluid at 0.3% concentration, which was about 28.0% to 32.0% higher than the pure water in spiral fluted tube equipped with twisted tape. Empirical correlation for the thermal process was developed and represented in terms of Nusselt number. Numerical simulation has been carried out on present heat exchanger to analyze both flow field and heat transfer using ANSYS FLUENT package 14. The comparison between experimental and numerical results showed good agreement.
Heat exchanger, spiral fluted tube, twisted tape, nanofluid, coefficient, surface vibration.
Mechanical Engineering Department, College of Engineering, Al-Mustansirya University, Baghdad, Mechanical Engineering Department, College of Engineering, Al-Mustansirya University, Baghdad, Mechanical Engineering Department, College of Engineering, Al-Mustansirya University, Baghdad