A review of multi-phase and single-phase models in the numerical simulation of nanofluid flow in heat exchangers

Various types of heat exchangers have many applications in industrial and engineering fields to improve heat transfer rate (HTR). The techniques of heat transfer enhancement which are active, passive, and hybrid are discussed in the present review paper. One of passive methods to enhance HTR is the use of nanofluids. This article provides the governing equations of nanofluid flows and discusses their modeling methods, including single-phase and two-phase. Advanced investigations considered single-phase and two-phase flow regimes are summarized. Comparing single-phase models (SPMs) and two-phase models (TPMs), most researchers concluded that numerical modeling based on TPMs experiences a better prediction compared to the SPMs. However, there are conflicting results among the researchers and it is not confirmed which model is better. This review paper aims to analyze the examinations on SPMs and TPMs in heat exchangers to assess the impact of these approaches on the prediction of the characteristics of nanofluids in these devices.

Automated summary

This review paper discusses active, passive, and hybrid methods to enhance heat transfer rate, with a focus on the passive method of using nanofluids. The governing equations and modeling methods for nanofluid flows are provided, along with a summary of advanced investigations on single-phase and two-phase flow regimes. Although there are conflicting results among researchers, most conclude that numerical modeling based on two-phase models provides a better prediction than single-phase models.