Self-cleaning compact heat exchangers: The role of two-phase flow patterns in design and optimization
Journal article, 2019

Fouling on heat exchanger surfaces significantly impedes heat recovery from exhaust gases in many industrial applications. An introduction of the process of self-cleaning possibly represents an efficient solution to this well-known problem. Even if special treatments of the surfaces can help to protect them from fouling, it is still not well understood how to properly design heat exchangers in order to promote the self-cleaning process. In the present study, we investigate by means of Lattice-Boltzmann-based simulations the pivotal role of two-phase flow patterns and condensation-related phenomena in understanding the mechanisms that promote the self-cleaning, and, consequently, a stable heat recovery. In particular, we identify optimal flow conditions and two-phase flow characteristics that allow a clean and efficient operation of compact heat exchangers. Our results indicate that low heat duties and flow rates, which induce the condensation of small and motile droplets able to collect gas impurities, are beneficial for provoking and sustaining self-cleaning mechanisms. We therefore suggest that an effective design of self-cleaning heat exchangers should primarily be governed by principles of two-phase flow, rather than by the heat transfer duty. This work thus represents a step forward in identifying and proposing a procedure for an optimal design of heat exchangers to facilitate an effective heat recovery process from a wider range of exhaust gas mixtures.

two-phase flows

dropwise condensation

self-cleaning

exhaust gases

heat recovery

Author

Dario Maggiolo

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Srdjan Sasic

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Henrik Ström

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

International Journal of Multiphase Flow

0301-9322 (ISSN)

Vol. 112 1-12

Coated heat exchangers as self-cleaning producer gas condensers

Swedish Energy Agency, 2017-01-01 -- 2018-12-31.

Driving Forces

Sustainable development

Innovation and entrepreneurship

Areas of Advance

Production

Energy

Subject Categories

Energy Engineering

Other Engineering and Technologies not elsewhere specified

Fluid Mechanics and Acoustics

Roots

Basic sciences

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

DOI

10.1016/j.ijmultiphaseflow.2018.12.006

More information

Latest update

2/20/2019