Experimental study on the droplet formation around pins of different geometry for the design of a compact falling-droplet absorber
| Autor: | Fabrizio Cola, Jonathan Hey, Alessandro Romagnoli |
|---|---|
| Přispěvatelé: | School of Mechanical and Aerospace Engineering, Energy Research Institute @ NTU (ERI@N) |
| Rok vydání: | 2018 |
| Předmět: |
Fluid Flow and Transfer Processes
Coalescence (physics) Materials science business.industry 020209 energy Refrigerator car 3D printing Geometry 02 engineering and technology Absorber Condensed Matter Physics Sizing law.invention Droplet Physics::Fluid Dynamics law Mass transfer Mechanical engineering [Engineering] Physics::Atomic and Molecular Clusters 0202 electrical engineering electronic engineering information engineering Absorption refrigerator Droplet flow business Adiabatic process |
| Zdroj: | Heat and Mass Transfer. 54:3599-3616 |
| ISSN: | 1432-1181 0947-7411 |
| DOI: | 10.1007/s00231-018-2381-8 |
| Popis: | Absorber downsizing for the development of compact absorption chillers is a known challenge of this type of refrigerator. Past studies have revealed how a droplet flow regime can increase the interface area and enhance absorption rates, especially during the droplet formation. This study proposes a space-efficient design for an adiabatic absorber based on a bank of solid pins coupled with a droplet flow regime. Manufacturing through 3D printing technique is used to study the effect of different fin shapes during droplet formation. Droplet behavior is firstly studied analytically through a variational approach. Experiments on pure water are then carried out to validate the model and produce design guidelines for a H2O-LiBr absorber. Results show that the analytical model is more accurate in the regions close to the droplet bottom. The rhomboidal geometry with 120° returned the smallest droplet volume without allowing coalescence of more droplets, ensuring the maintenance of droplet flow and a high surface area for mass transfer. Disturbances in the droplet profiles were observed, caused by the pin-droplet interaction. A map has been then created to allow a quick sizing of the absorber and find its main geometrical and operational features. |
| Databáze: | OpenAIRE |
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