Simulation of pool boiling of nanofluids by using Eulerian multiphase model

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Simulation of pool boiling of nanofluids by using Eulerian multiphase model Mohammed Saad Kamel1,2   · Mohamed Sobhi Al‑agha1 · Ferenc Lezsovits1 · Omid Mahian3,4 Received: 1 June 2019 / Accepted: 8 December 2019 © The Author(s) 2019

Abstract In the present work, a new simulation of nanofluid/vapor two-phase flow inside the 2-D rectangular boiling chamber was numerically investigated. The Eulerian–Eulerian approach used to predict the boiling curve and the interaction between two phases. The surface modification during pool boiling of silica nanofluid represented by surface roughness and wettability is put into the account in this simulation. New closure correlations regarding the nucleation sites density and bubble departure diameter during boiling of silica nanofluid were inserted to extend the boiling model in this work. Besides, the bubble waiting time coefficient which involved in quenching heat flux under heat flux partitioning HFP model was corrected to improve the results of this study. The numerical results validated with experimental works in the literature, and they revealed good agreements for both pure water and nanofluids. The results found that when improving the heat flux partitioning model HFP by considering the surface modification of nucleate pool boiling parameters, it will give more mechanistic sights compared to the classical model, which is used for predicting of boiling heat transfer of pure liquid. Keywords  Nucleate boiling · HFP model · Wettability · Pool boiling · Nanofluids Abbreviation UDFs User defined functions RPI Rensselaer polytechnic institute HFP Heat flux partitioning FVM Finite volume method CHF Critical heat flux PBHTC Pool boiling heat transfer coefficient List of symbols qtotal (kW m−2) Total heat flux density qquen (kW m−2) Quenching heat flux qevap (kW m−2) Evaporative heat flux qconv (kW m−2) Convection heat flux * Mohammed Saad Kamel [email protected]; [email protected] 1



Department of Energy Engineering, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Muegyetem rkp. 3, Budapest 1111, Hungary

2



Department of Mechanical Techniques, Al‑Nasiriya Technical Institute, Southern Technical University, Thi‑Qar, Al‑Nasiriya 64001, Iraq

3

School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an, China

4

Department of Mechanical Engineering, Quchan University of Technology, Quchan, Iran



P (kPa) Pressure system Dbw (mm) Bubble departure diameter dp (nm) Particle size N (sites cm−2) Nucleation site density Ra (nm) The surface roughness Tw (K) Wall temperature Cw (–) Bubble waiting time coefficient Tsat (K) Saturation temperature 𝜌l (kg m−3) The density of the liquid Kl (W m−1 K−1) The thermal conductivity of the liquid Greek letters 𝜑 (%) Volume friction 𝜇 (Ps a) Viscosity 𝜃 (°) Contac angle 𝛽 (–) Wettability improvement parameter Subscripts atm Atmospheric sat Saturation g Gases l Liquid eff Effective w Wall sup Superheat quen Quenching

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evap Ev