Institute of Process Engineering

Chair of Thermal Process Engineering

Contact heat transfer and heat conduction in packed beds of edged particles

A central parameter of thermal DEM is the particle-particle heat transfer coefficient during binary contacts. Contact heat transfer is always important when heat is transmitted between particles of the bed in order to conduct thermochemical processes, but in presence of steep temperature profiles, it can also be significant when heat is supplied from the gas phase. Despite of its central role, simplified models, the validity of which is questionable even in the case of equally sized spheres, are used to calculate contact heat transfer. Despite many practical applications, any reliable background is missing in the case of edged, polyhedral particles.

Particle-particle heat transfer coefficients, α_pp, that can be used in DEM (or DEM/CFD) for static, moving, or mechanically agitated particle systems, can be derived from the effective thermal conductivity of respective packed beds, λ_bed, but the pre-factor of the linear relationship between those two quantities needs to be tuned. In this research, it is needed to use measured or simulated λ_bed data in order to expand a standard model for λ_bed to applicability with arbitrarily non-spherical particles, and then apply relationships that connect λ_bed with α_pp on theoretical grounds in order to calculate values of α_pp for use in thermal DEM. This will be done in two stages. First, for beds of monodisperse particles of different shapes; Second, for binary mixtures of particles that differ in shape, size, or material. In both cases, the results of thermal equilibration experiments will be used which will be conducted in a rotary drum. Mixing initially segregated fractions of hot and cold particles would ideally unveil the kinetics of interparticle heat transfer. Moreover, DEM simulations of the simultaneous mechanical and thermal mixing of particles in the drum are also necessary for this envisaged approach. The main goal of the research is based on the overarching idea of transcription from λ_bed, reliable rules for the computation of α_pp for both homo-contacts between same as well as hetero-contacts between different particles.

This research is part of Collaborative Research Center/Transregios 287 "Bulk-Reaction." More information on the whole collaborative project can be found on site: https://bulk-reaction.de/.

2020

• Samadi, F., & Kazemi, N. (2020). Exergoeconomic analysis of zeotropic mixture on the new proposed organic Rankine cycle for energy production from geothermal resources. Renewable Energy, 152, 1250–1265. https://doi.org/10.1016/j.renene.2020.01.038

2016

• Karimi, S., Kazemi, S., & Kazemi, N. (2016). Syneresis measurement of the HPAM-Cr (III) gel polymer at different conditions: An experimental investigation. Journal of Natural Gas Science and Engineering, 34, 1027–1033. https://doi.org/10.1016/j.jngse.2016.08.011

• Kazemi, N., & Samadi, F. (2016). Thermodynamic, economic and thermo-economic optimization of a new proposed organic Rankine cycle for energy production from geothermal resources. Energy Conversion and Management, 121, 391–401. https://doi.org/10.1016/j.enconman.2016.05.046

Confereces

• Predicting the Refractive Index in Binary Systems of Ionic Liquids and Alcohol binary, 26th Regional Symposium of Chemical Engineering, Kuala Lumpur, Malaysia, October 2019.
• Investigation into effect of different anionic surfactants on hydrate formation velocity and its storage capacity, The Third National Conference on Oil, Gas and Petrochemicals, Iran, Gachsaran, 2014.
• Modifying Hansen Won and thermodynamic model for more accurate prediction of wax deposit formation, The Third National Conference on Oil, Gas and Petrochemicals, Iran, Gachsaran, 2014.