Performance analysis of Al2O3–R718 nanorefrigerant turbulent flow through a flooded chiller tube: a numerical investigation

Abstract

The current study presents a numerical analysis of the heat transfer and the pressure drop quantification of Al 2 O 3-R718-based nanorefrigerant flow through a circular tube of a flooded evaporator chiller. R718 (water) is one of the most widely used secondary refrigerants in HVAC applications. The flow Reynolds number through a chiller tube of a typical 325 TR capacity water chiller is between 13,000 and 33,000. Therefore, the nanorefrigerant flow was simulated at Reynolds number (Re) varying between 13,000 and 33,000 for three distinct particle volume fractions (ϕ): 0.25%, 0.5% and 1.0%. The temperature variation in the computational domain was between 278 and 288 K. Therefore, temperature-dependent thermophysical property values were utilised in the present study in order to get more reliable results. It was found that the surface heat flux is higher for Al 2 O 3-R718 nanorefrigerants in comparison with that of water. The average surface heat flux increases with increase in particle volume fraction, but the pumping power also elevates with particle volume fraction. The turbulence in the nanorefrigerant flow was also analysed and discussed. Furthermore, the entropy generation analysis revealed that the entropy generation rate for Al 2 O 3-R718 nanorefrigerants was lower in comparison with that of pure R718. The overall performance of the nanorefrigerant was analysed using two different thermal performance parameters, and it was found that the thermal performance parameter was higher than 1 for all the flow scenarios investigated in the current simulation.

Carbon-Based Nanofluids and Their Advances towards Heat Transfer Applications—A Review

“…It is evident from the literature that there are many researchers investigated the performance properties (i.e., heat transfer coefficient and viscosity) of nanoparticles applied to the refrigerants in AC&R systems including copper (Cu), aluminum (Al), nickel (Ni), copper oxide (CuO), zinc oxide (ZnO), aluminum oxide (Al 2 O 3 ), titanium oxide (TiO 2 ), and other metal nanoparticles [ 325 , 419 , 420 , 421 , 422 , 423 , 424 , 425 , 426 , 427 , 428 , 429 , 430 , 431 , 432 , 433 , 434 ]. However, only a limited number of research work is available for ND, graphene, and CNTs, which can be summarized in Table 10 .…”

Simulation and Investigation of Nano-Refrigerant Fluid Characteristics With the Two-Phase Flow in Microchannel

“…The surface temperature increased with the test section, and heat transfer from the boiling of two-phase flow nucleate in a microchannel is affected by boiling the core heat transfer nucleates and was slightly affected by convective heat transfer. Nair et al (2020) presented the analysis of numerical heat transfer and the quantification for the pressure drop by the flooded evaporator chiller Al2O3 -R718-based nanorefrigerant flow. R718 (water) was one of the secondary coolants most commonly used in HVAC applications.…”