Numerical analysis of flow and heat characteristic around micro-ribbed tube in heat exchanger system

In order to improve the energy utilization rate, this paper analyzes the flow around the cylinder in the tube-row channel heat exchanger through numerical simulation. Effects of micro-rib structure types (vertical rib and ring rib), number of ribs (N = 0, 4, 6, 8), height of ribs (H = 2, 3, 4 mm), pitch diameter ratio (ST/D = 1.5, 2, 2.5), mass fractions (omega = 0-0.5%) and Reynolds numbers (Re = 514-1205) on the flow and heat transfer characteristics of tube-row channel heat exchangers are analyzed. Results showed that TiO2-H2O nanofluids can improve the comprehensive performance of heat exchanger, and when the mass fraction is 0.4%, the tube-row channel heat exchanger has the best performance. For heat exchangers with different types and structural parameters, the adjustment of the number of ribs, the height of ribs, the ratio of transverse pitch diameter and the use of nanofluids can increase Nusselt numbers by 53.63%, 57.25%, 52.38% and 12.93% at maximum, respectively. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study analyzed the effects of different parameters on the flow and heat transfer characteristics of tube-row channel heat exchangers through numerical simulation. It was found that TiO2-H2O nanofluids can improve the performance of heat exchangers, with the best results achieved at a mass fraction of 0.4%. Adjusting the number of ribs, rib height, pitch diameter ratio, and using nanofluids can significantly increase the Nusselt numbers.