Bubble Dynamics and Enhanced Heat Transfer During High-Pressure Pool Boiling on Rough Surface

2019 ◽  
Vol 33 (2) ◽  
pp. 309-321
Author(s):  
Avdhoot Walunj ◽  
A. Sathyabhama
Author(s):  
Calvin H. Li ◽  
Ting Li ◽  
Brian Kanney

An experimental study of the pool boiling two-phase heat transfer on a sintered Cu microparticle porous structure module surface is conducted. Enhanced heat transfer capacity of this module surface has been reported, and the boiling characteristics have been investigated. The bubble dynamics and nucleate size distribution have been compared to the theoretical predictions, and the speculated mechanisms have been discussed.


Author(s):  
Nanxi Li ◽  
Amy Rachel Betz

In this work, we present the design and fabrication a high-pressure pool boiling facility to conduct pool boiling experiments on horizontal heated surfaces under elevated pressures, up to 20 bar. Previous research has shown that micro- and/or nano-structured surfaces and coated surfaces will increase heat transfer coefficients up to one order of magnitude at atmospheric pressure. However, most boiling applications are subjected to high pressure, especially in the power industry. Pressure inside a boiling water reactor in a nuclear power plant will reach as high as 75 atm (75.99 bar). In order to determine how heat transfer is enhanced at increased pressures, with deionized water and refrigerants, on modified surfaces, a special experimental setup needs to be designed and fabricated. Difficulties in making such an experimental setup come from stabilizing the system pressure, sealing the test setup and visualizing the boiling conditions in the vessel. Both advantages and disadvantages of this design will be discussed and possible methods for improvements will be proposed. Preliminary test results on a plane copper surface are also included. Future research will be focusing on boiling of water and refrigerants on micro-structured copper surfaces, graphene coated, and Teflon© coated surfaces under high pressure.


2016 ◽  
Vol 745 ◽  
pp. 032132 ◽  
Author(s):  
E. Teodori ◽  
T. Palma ◽  
T. Valente ◽  
A.S. Moita ◽  
A.L.N. Moreira

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Jie Qin ◽  
Zhiguo Xu ◽  
Xiaofei Ma

Abstract Based on the newly developed geometrical model of open-cell metal foam, pool boiling heat transfer in open-cell metal foam, considering thermal responses of foam skeletons, is investigated by the phase-change lattice Boltzmann method (LBM). Pool boiling patterns are obtained at different heat fluxes. The effects of pore density and foam thickness on bubble dynamics and pool boiling heat transfer are revealed. The results show that “bubble entrainment” promotes fluid mixing and bubble sliding inside metal foam. Based on force analysis, the sliding bubble is pinned on the heating surface and cannot lift off completely at high heat flux due to the increasing surface tension force. Pool boiling heat transfer coefficient decreases with increasing pore density and foam thickness due to high bubble escaping resistance.


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