Wang_158822.pdf (1.84 MB)
Download file

Gas-phase transport and entropy generation during transient combustion of single biomass particle in varying oxygen and nitrogen atmospheres

Download (1.84 MB)
journal contribution
posted on 10.05.2021, 12:39 by LINWEI Wang, Nader Karimi, Manosh C Paul
Transient combustion of a single biomass particle in preheated oxygen and nitrogen atmospheres with varying concentration of oxygen is investigated numerically. The simulations are rigorously validated against the existing experimental data. The unsteady temperature and species concentration fields are calculated in the course of transient burning process and the subsequent diffusion of the combustion products into the surrounding gases. These numerical results are further post processed to reveal the temporal rates of unsteady entropy generation by chemical and transport mechanisms in the gaseous phase of the reactive system. The spatio-temporal evolutions of the temperature, major chemical species including CO, CO2, O2, H2 and H2O, and also the local entropy generations are presented. It is shown that the homogenous combustion of the products of devolatilisation process dominates the temperature and chemical species fields at low concentrations of oxygen. Yet, by oxygen enriching of the atmosphere the post-ignition heterogeneous reactions become increasingly more influential. Analysis of the total entropy generation shows that the chemical entropy is the most significant source of irreversibility and is generated chiefly by the ignition of volatiles. However, thermal entropy continues to be produced well after termination of the particle life time through diffusion of the hot gases. It also indicates that increasing the molar concentration of oxygen above 21% results in considerable increase in the chemical and thermal entropy generation. Nonetheless, further oxygen enrichment has only modest effects upon the thermodynamic irreversibilities of the system

Funding

Thermally Driven Heat Pump Based on an Integrated Thermodynamic Cycle for Low Carbon Domestic Heating (Therma-Pump)

Engineering and Physical Sciences Research Council

Find out more...

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

International Journal of Hydrogen Energy

Volume

43

Issue

17

Pages

8506 - 8523

Publisher

Elsevier BV

Version

AM (Accepted Manuscript)

Rights holder

© 2018 Hydrogen Energy Publications LLC

Publisher statement

This paper was accepted for publication in the journal International Journal of Hydrogen Energy and the definitive published version is available at https://doi.org/10.1016/j.ijhydene.2018.03.074

Acceptance date

09/03/2018

Publication date

2018-04-04

Copyright date

2018

ISSN

0360-3199

Language

en

Depositor

Dr LINWEI Wang. Deposit date: 7 May 2021