EMERGENCY COOLING OF SUPERHEATED SURFACES BY NANOFLUIDS ADDITIVES IN STOP- AND NON-STOP MODES OF HEAT LOAD RISE

Author:

Moraru V.N.ORCID,Komysh D.V.ORCID

Abstract

Early [Technical Physics Letters, 2016, Vol. 42, P. 677–681. — https://doi.org/10.1134/ S106378501607004X] we have shown the possibility of emergency cooling of an overheated Ni/Cr surface using additives of aluminosilicate nanofluids (AlSi-NF) at the time of developed film boiling of water (crisis), provided that the increase in thermal load is stopped and its fixation at the level of Q » 1.0 MW/m2, exceeding the critical heat flux (CHF) of water (0.7 MW/m2). However, in real operating conditions of cooling systems (especially for nuclear reactors), emergency situations sometimes arise in which it is very problematic to immediately turn off the heat load supply or maintain it at a certain predetermined level. In this regard, in this work, on a fully automated stand, the peculiarities of eliminating the water boiling crisis and emergency cooling of the overheated surface of the mini-reactor heater by injecting a portion of hot AlSi-NF in conditions of film boiling of water and a steady increase in heat load were studied, and the results were compared with previously obtained in the mode of stopping the rise of the thermal load. The test was carried out on an aqueous AlSi-NF nanofluid obtained on the basis of a natural mixture of aluminosilicates montmorillonite + palygorskite (Ukraine). The boiling-overheating-cooling curves, as well as the time dependences of the heat transfer coefficient and the heating surface temperature, were recorded in automatic real-time mode. Emergency cooling of the overheated surface (from 600 to 125 °C) after the introduction of a portion of hot AlSi-NF occurred in a matter of minutes due to a sharp increase in the heat transfer coefficient α up to 55,000 W/(m2.K). Such a phenomenon of a sharp intensification of heat transfer and a 3-fold increase in the specific heat flux (qsp) during boiling of AlSi-NF compared to the base liquid (water) is explained by the deposition on the heating surface of a gel-like layer of nanoparticles with high hydrophilicity and mobility, which can sharply increase nucleate boiling and convection. Regardless of the mode of supplying the heat load, the principal possibility of overcoming the boiling crisis and emergency cooling of the superheated surface with the addition of AlSi-NF nanofluid has been established, for a time sufficient to eliminate the accident. Bibl. 27, Fig. 4, Tab. 1.

Publisher

The Gas Institute of the National Academy of Sciences of Ukraine

Subject

General Earth and Planetary Sciences,General Environmental Science

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3