Open Access

ARTICLE

Optimal Pitch Size of a Biphilic Surface for Boiling Heat Transfer at Subatmospheric Pressures

by Ivan Malakhov^1,*, Anton Surtaev^1,2, Vladimir Serdyukov^1,2, Ali Kosar³, Alexander Pavlenko¹

1 The Laboratory of Low-Temperature Thermophysics, Kutateladze Institute of Thermophysics, Novosibirsk, 630090, Russia
2 Physical Department, Novosibirsk State University, Novosibirsk, 630090, Russia
3 Center of Excellence for Functional Surfaces and Interfaces (EFSUN), Faculty of Engineering and Natural Sciences (FENS), Sabanci University, Orhanli, Tuzla, Istanbul, 34956, Turkey

* Corresponding Author: Ivan Malakhov. Email:

(This article belongs to the Special Issue: Boiling Heat Transfer: Fundamentals and Improvement Techniques)

Frontiers in Heat and Mass Transfer 2024, 22(6), 1645-1660. https://doi.org/10.32604/fhmt.2024.056664

Received 27 July 2024; Accepted 24 October 2024; Issue published 19 December 2024

Abstract

To date, using biphilic surfaces is one of the most promising methods for enhancing heat transfer and critical heat flux during boiling simultaneously. However, most of studies on the effect of biphilic surfaces on boiling performance have been carried out under atmospheric pressure conditions. In this context, the issues of heat transfer enhancement and stabilization of the boiling process at subatmospheric pressures are particularly critical due to the interesting characteristics of boiling heat transfer and bubble dynamics at subatmospheric pressures and their practical significance including aerospace applications. This paper investigates the effect of the pitch size between hydrophobic spots on a biphilic surface on heat transfer and bubble dynamics during boiling at subatmospheric pressures (from 11.2 kPa up to atmospheric pressure). The data analysis using infrared thermography demonstrated that the maximum heat transfer rate was achieved on a surface with a uniform pitch size (6 mm) at all pressures. In this case, the heat transfer enhancement, compared a bare surface, reached 3.4 times. An analysis of the departure diameters of bubbles based on high-speed visualization indicated that the optimal configuration of the biphilic surface corresponds to the pitch size equal to the bubble departure diameter. Using high-speed visualization also demonstrated that an early transition to film boiling was evident for configurations with a very high density of hydrophobic spots (pitch size of 2 mm).

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