CHF enhancement by honeycomb porous plate in saturated pool boiling of nanofluid

Abstract

One strategy for severe accidents is in-vessel retention (IVR) of corium debris. In order to enhance the capability of IVR in the case of a severe accident involving a light-water reactor, methods to increase the critical heat flux (CHF) should be considered. Approaches for increasing the IVR capability must be simple and installable at low cost. Moreover, cooling techniques for IVR should be applicable to a large heated surface. Therefore, as a suitable cooling technology for required conditions, we proposed cooling approaches using a honeycomb porous plate for the CHF enhancement of a large heated surface in a saturated pool boiling of pure water. In this paper, CHF enhancement by the attachment of a honeycomb-structured porous plate to a heated surface in saturated pool boiling of a TiO 2 -water nanofluid was investigated experimentally under atmospheric pressure. As a result, the CHF with a honeycomb porous plate increases as the nanoparticle concentration increases. The CHF is enhanced significantly up to 3.2 MW/m 2 at maximum upon the attachment of a honeycomb porous plate with 0.1 vol.% nanofluid. To the best of the author's knowledge, under atmospheric pressure, a CHF of 3.2 MW/m 2 is the highest value for a relatively large heated surface having a diameter exceeding 30 mm.

Retraction: Process of liquid supply to heated surface by a honeycomb porous plate for critical heat flux enhancement

“…In recent years, as described by Okawa et al (2014), research on the improvement of 𝑞𝑞 CHF has been conducted using nanofluids Cheng et al, 2008;Kim, 2011;Kwark et al, 2010;Mori et al, 2014Mori et al, , 2015aMori et al, , 2016Mt Aznam et al, 2015Okawa et al, 2012;You et al, 2003). The improvement rate is in a wide range of 1.1 to 3 times compared to the bare surface.…”

“…Mori and Okuyama (2009) proposed a surface modification by attaching a honeycomb porous plate (HPP) to a heated surface. For upward-facing φ 30 mm and φ 50 mm heater surfaces with an HPP attached, saturated pool boiling 𝑞𝑞 CHF under atmospheric pressure with water was reported to be enhanced up to 2.5 times as compared to a bare surface (Mori et al, 2016;. The HPP provides two vital parts, which are the porous part and vapor escape channels.…”

Recent Advances in the Critical Heat Flux Amelioration of Pool Boiling Surfaces Using Metal Oxide Nanoparticle Deposition

“…Moreover, Lotfi and Shafii [209] reported CHF reduction for 0.5-4 wt% Ag and 0.125-1.0 wt% TiO 2 nanofluids as the nanoparticle concentration decreases. The boiling properties of a honeycomb porous plate, which covers a 30-mm diameter heating surface that was placed in water-based TiO 2 nanofluids was studied by Mori et al [210,211]. They achieved considerable CHF amelioration equal to 320 W/cm 2 by increasing the nanoparticle concentration to 0.1 vol.%.…”

Effect of honeycomb porous plate on critical heat flux in saturated pool boiling of artificial seawater

“…Various methods have been proposed for enhancing IVR performance and reliability, including using nanofluids [2][3][4][5] or surfactant solutions [6][7][8] instead of water and modifying the RPV outer wall [9][10][11][12][13][14]. Mori et al [15] proposed a combination of two approaches, the adoption of TiO 2 nanofluid as coolant and the attachment of a honeycomb porous plate (HPP) to the RPV outer wall to improve the critical heat flux (CHF). They found that the CHF increased when using the nanofluid concentrations tested (0 vol%, 0.001 vol%, and 0.1 vol%), with a CHF of 3.2 MW/m 2 for 0.1 vol% nanofluid with an HPP attached to the surface.…”