Simulation of Taylor flow evaporation for bubble-pump applications

•Simulations are performed for flow evaporation in continuously heated bubble pumps.•A Volume-of-Fluid phase-change simulation formulation is developed and validated.•Simulation results are used to assess analytic models for Taylor flow evaporation.•Kinematic and hydrodynamic Taylor flow closure mod...

Celý popis

Uložené v:
Podrobná bibliografia
Vydané v:International journal of heat and mass transfer Ročník 116; číslo C; s. 231 - 247
Hlavní autori: Rattner, Alexander S., Garimella, Srinivas
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: Oxford Elsevier Ltd 01.01.2018
Elsevier BV
Elsevier
Predmet:
Absorption refrigeration
Bubble pump
Bubbles
Computer simulation
Deviation
Flow boiling
Fluid mechanics
Generators
Heat transfer
Heat transfer coefficients
Hydrodynamic pressure
Mathematical models
Phase transitions
Pressure drop
Refrigeration
Slug flow
Studies
Taylor flow
Two phase flow
Void fraction
Volume of fluid
Absorption refrigeration
Bubble pump
Flow boiling
Volume of fluid
ISSN:0017-9310, 1879-2189
On-line prístup:Získať plný text
Tagy: Pridať tag
Žiadne tagy, Buďte prvý, kto otaguje tento záznam!
Popis
Shrnutí:•Simulations are performed for flow evaporation in continuously heated bubble pumps.•A Volume-of-Fluid phase-change simulation formulation is developed and validated.•Simulation results are used to assess analytic models for Taylor flow evaporation.•Kinematic and hydrodynamic Taylor flow closure models are individually validated.•A new laminar Taylor flow evaporation heat transfer model is validated.•Findings confirm the use of an proposed model for continuously heated bubble pumps. Single-pressure absorption systems incorporate bubble-pump generators (BPGs) for refrigerant separation and passive fluid circulation. In conventional spot-heated BPGs, heat is transferred over a small area, requiring high source temperatures. Distributed-heated BPGs receive thermal input over most of the component surface, enabling low temperature operation. In this investigation, a Volume-of-Fluid phase-change simulation formulation is developed and validated. This approach is applied to the evaporating Taylor flow pattern in distributed-heated BPGs. A 2-D axisymmetric simulation is performed, which yields detailed information about the developing heat transfer and two-phase flow phenomena. Results are used to assess predicted trends and sub-models from a 1-D segmented BPG model. Close agreement is obtained between segmented model and simulation results for bubble rise velocity (5–7% deviation), bubble and slug lengths, void fraction (3%), and hydrodynamic pressure drop (18%). Specifying average Taylor bubble lengths from the simulation as an input to the segmented model reduces hydrodynamic pressure drop deviation to 6%. Simulated flow-evaporation heat transfer coefficients are significantly higher than those predicted using analytic models from the literature. A new flow evaporation heat transfer correlation that accounts for developing slug flow effects is proposed, and yields close agreement with simulation results for heat transfer coefficient (AAD=11%) and overall heat transfer rate (2%). Overall, this investigation provides validation for a distributed-heated BPG modeling approach, which can enable passive refrigeration for diverse applications.
Bibliografia:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 14
USDOE
FG02-97ER25308; AC02-05CH11231
ISSN:0017-9310
1879-2189
DOI:10.1016/j.ijheatmasstransfer.2017.08.110