Visualization and experimental analysis of Geyser boiling phenomena in two-phase thermosyphons

Pabón, Nelson Yurako Londoño; Mera, Juan Pablo Flórez; Vieira, Gabriel de Deus; Mantelli, Marcia

doi:10.1016/j.ijheatmasstransfer.2019.06.052

Cited by 47 publications

(2 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Se observa que ambos termosifones presentan grandes oscilaciones en las temperaturas cuando la tasa de calor transferida fue inferior a 25 W. Estas oscilaciones pueden ser atribuidas al fenómeno de Geyser Boiling, el cual es caracterizado por las oscilaciones simetrías de la temperatura del evaporador y condensador [11], es decir, cuando aumenta abruptamente la temperatura del evaporador, las temperaturas de la zona adiabática y el condensador disminuyen abrupta e instantáneamente. De la misma forma, cuando la temperatura del evaporador disminuye abruptamente, las temperaturas de las demás secciones aumentan instantáneamente, evidenciando el ciclo de liberación y formación de burbujas de vapor durante el régimen de Geyser Boiling [13]- [14].…”

Section: Resultsunclassified

Estudio experimental de termosifones bifásicos con relación largo-diámetro interno constante para aplicaciones geotérmicas

2022

Congreso Iberoamericano De Ingeniería Mecánica-Cibim 2022

View full text Add to dashboard Cite

En este trabajo se estudió experimentalmente la validez de la relación largo-diámetro interno (L/D) como herramienta de escalamiento en termosifones bifásicos extralargos para aplicaciones geotérmicas. Fueron estudiados dos termosifones con diferentes dimensiones, manteniendo la relación L/D=110. Los resultados obtenidos muestran que el termosifón de menor tamaño y mayor diámetro operó a temperaturas de vapor mayores (hasta de 20ºC) y resistencias térmicas menores (hasta 40%), mostrando que la relación L/D no es suficiente para escalar termosifones sin perder informaciones fundamentales de la operación de estos dispositivos. Fue propuesta una longitud característica, dada por D 2 /L, permite reducir significativamente las diferencias entre las resistencias térmicas de ambos termosifones. Sin embargo, se sugiere que el escalamiento de termosifones bifásicos extralargos no envuelva solo aspectos geométricos del dispositivo, sino que también incluya propiedades termofísicas del fluido de trabajo, las cuales son afectadas significativamente por la temperatura de operación del vapor.

show abstract

Section: Resultsunclassified

Estudio experimental de termosifones bifásicos con relación largo-diámetro interno constante para aplicaciones geotérmicas

2022

Congreso Iberoamericano De Ingeniería Mecánica-Cibim 2022

View full text Add to dashboard Cite

show abstract

“…Once generated, the steam passed through the adiabatic part to the condenser and condensed at the upper part of the TPCT before flowing back to the evaporator as a liquid substance again. At the same time, the vaporization from the evaporator started to condense again [22,27,28]. Two-phase flow patterns within the circular oscillating heat pipe made of glass with a diameter of 2 mm was also studied.…”

Section: Introductionmentioning

confidence: 99%

Archives of Thermodynamics

Chompookham,

Sichamnan,

Bhuwakietkumjohn

et al. 2020

View full text Add to dashboard Cite

This research explored different types of two-phase flow patterns that influenced heat transfer rate by assessing rectangular two-phase closed thermosyphon (RTPCT) made from glass with the sides of equal length of 25.2 mm, aspect ratio 5 and 20, evaporation temperature of 50, 70, and 90 • C, working substance addition rate of 50% by volume of evaporator, and water inlet temperature at condensation of 20 • C. Upon testing with aspect ratios 5, three flow patterns emerged which were: bubble flow, slug flow and churn flow respectively. As per the aspect ratio 20, four flow patterns were discovered which were: bubble flow, slug flow, churn flow and annular flow, respectively. Aspect ratio 5 pertains characteristic which resulted in a shorter evaporation rate of the RTPCT than that of the aspect ratio 20, thus, a shorter flow distance from the evaporator section to heat releaser was observed. Therefore, flow patterns at aspect ratio 5 exhibited a faster flow velocity than that of the aspect ratio 20. Furthermore, changes of flow pattern to the one that is important for heat transfer rate can be easily achieved. Churn flow was the most important type of the flow for

show abstract

Effective energy management design of spent fuel dry storage based on hybrid control rod‐heat pipe

Kim

Bang

2020

Int J Energy Res

View full text Add to dashboard Cite

Spent fuel dry storage cask, which stores the spent fuel from wet storage facility to final processing, has been developed and managed. Even though thermal management mechanisms of dry storage casks secure the thermal integrity of the cask, improvement of thermal management capacity of dry storage cask would enhance thermal margin against unforeseen off-normal conditions with increasing specific storage capacity. Ulsan National Institute of Science and Technology (UNIST) CANister (UCAN) utilizing the new-type thermosyphon heat pipe, is under development as an advanced design of spent fuel dry storage cask. Hybrid control rod-heat pipe, which is an annular thermosyphon by containing neutron absorber, is a key component of UCAN. Heat removal performance of the hybrid control rod-heat pipe was analyzed bya series of experiment withtest facility simulating single fuel assembly with full height. The UCAN fuel assembly showed the reduced structural and fuel temperatures compared to bare fuel assembly of conventional cask designs, exhibitingimproved thermal margin. According to experimentally observed heat removal rate of the hybrid control rod-heat pipe, UCAN design could extend manageable thermal capacity from 13.3% to 33.8%. The removeddecay heat through hybrid control rod-heat pipe could be reused in electricity generation with stirling engine and thermoelectric devices improving energy management efficiency. Intermittent boiling accompanying geyser phenomena was frequently occurred inside the test section, and the boiling behaviors according to fill ratios (FRs) and operating pressures dominated the heat removal performances. The hydrostatic pressure owing to large aspect ratio affected differentiated thermal-hydraulic behaviors compared to conventional thermosyphons. To develop heat transfer and hydraulic models of the hybrid control rod-heat pipe, geyser phenomenon inside the test section wasdiscussed physically. This workexhibited the feasibility of UCAN design and provides fundamental physics on intermittent boiling of thermosyphon operating at sub-atmospheric pressures.

show abstract

Visualization and experimental analysis of Geyser boiling phenomena in two-phase thermosyphons

Cited by 47 publications

References 25 publications

Estudio experimental de termosifones bifásicos con relación largo-diámetro interno constante para aplicaciones geotérmicas

Estudio experimental de termosifones bifásicos con relación largo-diámetro interno constante para aplicaciones geotérmicas

Archives of Thermodynamics

Effective energy management design of spent fuel dry storage based on hybrid control rod‐heat pipe

Contact Info

Product

Resources

About