An experimental investigation of the effects of surface conditions on pool-boiling heat transfer for various materials

Shikha A. Ebrahim; Ece Alat; Faruk A. Sohag; Valerie Fudurich; Shi Chang; Fan Bill Cheung; Stephen M. Bajorek; Kirk Tien; Chris L. Hoxie

An experimental investigation of the effects of surface conditions on pool-boiling heat transfer for various materials

Shikha A. Ebrahim, Ece Alat, Faruk A. Sohag, Valerie Fudurich, Shi Chang, Fan Bill Cheung, Stephen M. Bajorek, Kirk Tien, Chris L. Hoxie

Research output: Contribution to conference › Paper › peer-review

8 Scopus citations

Abstract

Film boiling is an important phenomenon in the evaluation of an emergency core cooling system following a hypothetical loss of coolant accident (LOCA) in a nuclear reactor. In this study, an experimental test facility was designed and constructed with the purpose of performing high-temperature transient pool boiling quenching experiments for stainless steel (SS) and zirconium (Zr) cylindrical test samples. The fabricated samples have three embedded thermocouples between the inner surface of the rods and the boron nitride (BN) filler material. The focus of this research is to study the effects of liquid subcooling, surface oxidation and surface materials for the prescribed materials on the minimum film boiling temperature, Tmin. The samples were heated to a temperature well above the Tmin (up to 550^oC) then plunged vertically in a quiescent pool of subcooled and saturated distilled water. A data acquisition system was used to record the temperature of the embedded thermocouple locations over time. Data reduction was performed by using an inverse heat conduction code (DATARH) to calculate the surface temperature and the corresponding wall heat flux. A visualization study using a high-speed camera was conducted. Additionally, a characterization study using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS) methods was performed to quantify surface conditions. Results indicate that liquid subcooling has a strong influence on Tmin. The visualization study shows a very thin vapor formation around the rod for higher subcooling cases that explains the enhancement in the heat transfer. Also, the surface characterization shows the difference in surface condition of the SS and Zr that leads the vapor bubbles to depart differently in the nucleate boiling regime. Furthermore, the effect of surface oxidation is noticeable in the Zr rod compared to SS rod due to the oxidation kinematic of the substrate material. Finally, it is found that the surface properties have a significant impact on Tmin.

Original language	English
State	Published - 2017
Externally published	Yes
Event	17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017 - Xi'an, Shaanxi, China Duration: Sep 3 2017 → Sep 8 2017

Conference

Conference	17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017
Country/Territory	China
City	Xi'an, Shaanxi
Period	09/3/17 → 09/8/17

Funding

We are grateful to Faith R. Beck for her assistance in building the experimental set-up and to Brian R. Lowery for fabricating the test samples. The work performed at the Pennsylvania State University was supported by the U.S. Nuclear Regulatory Commission under Contract # NRC-HQ-60-14-G-0017.

Funders	Funder number
U.S. Nuclear Regulatory Commission	NRC-HQ-60-14-G-0017

Keywords

Minimum film boiling temperature
Oxidation
Surface characterizations
Transient pool boiling
Vertical rod

Cite this

Ebrahim, S. A., Alat, E., Sohag, F. A., Fudurich, V., Chang, S., Cheung, F. B., Bajorek, S. M., Tien, K., & Hoxie, C. L. (2017). An experimental investigation of the effects of surface conditions on pool-boiling heat transfer for various materials. Paper presented at 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017, Xi'an, Shaanxi, China.

@conference{63f012fa24244535a32c0d6a2882cd0d,

title = "An experimental investigation of the effects of surface conditions on pool-boiling heat transfer for various materials",

abstract = "Film boiling is an important phenomenon in the evaluation of an emergency core cooling system following a hypothetical loss of coolant accident (LOCA) in a nuclear reactor. In this study, an experimental test facility was designed and constructed with the purpose of performing high-temperature transient pool boiling quenching experiments for stainless steel (SS) and zirconium (Zr) cylindrical test samples. The fabricated samples have three embedded thermocouples between the inner surface of the rods and the boron nitride (BN) filler material. The focus of this research is to study the effects of liquid subcooling, surface oxidation and surface materials for the prescribed materials on the minimum film boiling temperature, Tmin. The samples were heated to a temperature well above the Tmin (up to 550oC) then plunged vertically in a quiescent pool of subcooled and saturated distilled water. A data acquisition system was used to record the temperature of the embedded thermocouple locations over time. Data reduction was performed by using an inverse heat conduction code (DATARH) to calculate the surface temperature and the corresponding wall heat flux. A visualization study using a high-speed camera was conducted. Additionally, a characterization study using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS) methods was performed to quantify surface conditions. Results indicate that liquid subcooling has a strong influence on Tmin. The visualization study shows a very thin vapor formation around the rod for higher subcooling cases that explains the enhancement in the heat transfer. Also, the surface characterization shows the difference in surface condition of the SS and Zr that leads the vapor bubbles to depart differently in the nucleate boiling regime. Furthermore, the effect of surface oxidation is noticeable in the Zr rod compared to SS rod due to the oxidation kinematic of the substrate material. Finally, it is found that the surface properties have a significant impact on Tmin.",

keywords = "Minimum film boiling temperature, Oxidation, Surface characterizations, Transient pool boiling, Vertical rod",

author = "Ebrahim, {Shikha A.} and Ece Alat and Sohag, {Faruk A.} and Valerie Fudurich and Shi Chang and Cheung, {Fan Bill} and Bajorek, {Stephen M.} and Kirk Tien and Hoxie, {Chris L.}",

note = "Publisher Copyright: {\textcopyright} 2016 Association for Computing Machinery Inc. All Rights Reserved.; 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017 ; Conference date: 03-09-2017 Through 08-09-2017",

year = "2017",

language = "English",

}

Ebrahim, SA, Alat, E, Sohag, FA, Fudurich, V, Chang, S, Cheung, FB, Bajorek, SM, Tien, K & Hoxie, CL 2017, 'An experimental investigation of the effects of surface conditions on pool-boiling heat transfer for various materials', Paper presented at 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017, Xi'an, Shaanxi, China, 09/3/17 - 09/8/17.

An experimental investigation of the effects of surface conditions on pool-boiling heat transfer for various materials. / Ebrahim, Shikha A.; Alat, Ece; Sohag, Faruk A. et al.
2017. Paper presented at 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017, Xi'an, Shaanxi, China.

Research output: Contribution to conference › Paper › peer-review

TY - CONF

T1 - An experimental investigation of the effects of surface conditions on pool-boiling heat transfer for various materials

AU - Ebrahim, Shikha A.

AU - Alat, Ece

AU - Sohag, Faruk A.

AU - Fudurich, Valerie

AU - Chang, Shi

AU - Cheung, Fan Bill

AU - Bajorek, Stephen M.

AU - Tien, Kirk

AU - Hoxie, Chris L.

PY - 2017

Y1 - 2017

N2 - Film boiling is an important phenomenon in the evaluation of an emergency core cooling system following a hypothetical loss of coolant accident (LOCA) in a nuclear reactor. In this study, an experimental test facility was designed and constructed with the purpose of performing high-temperature transient pool boiling quenching experiments for stainless steel (SS) and zirconium (Zr) cylindrical test samples. The fabricated samples have three embedded thermocouples between the inner surface of the rods and the boron nitride (BN) filler material. The focus of this research is to study the effects of liquid subcooling, surface oxidation and surface materials for the prescribed materials on the minimum film boiling temperature, Tmin. The samples were heated to a temperature well above the Tmin (up to 550oC) then plunged vertically in a quiescent pool of subcooled and saturated distilled water. A data acquisition system was used to record the temperature of the embedded thermocouple locations over time. Data reduction was performed by using an inverse heat conduction code (DATARH) to calculate the surface temperature and the corresponding wall heat flux. A visualization study using a high-speed camera was conducted. Additionally, a characterization study using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS) methods was performed to quantify surface conditions. Results indicate that liquid subcooling has a strong influence on Tmin. The visualization study shows a very thin vapor formation around the rod for higher subcooling cases that explains the enhancement in the heat transfer. Also, the surface characterization shows the difference in surface condition of the SS and Zr that leads the vapor bubbles to depart differently in the nucleate boiling regime. Furthermore, the effect of surface oxidation is noticeable in the Zr rod compared to SS rod due to the oxidation kinematic of the substrate material. Finally, it is found that the surface properties have a significant impact on Tmin.

AB - Film boiling is an important phenomenon in the evaluation of an emergency core cooling system following a hypothetical loss of coolant accident (LOCA) in a nuclear reactor. In this study, an experimental test facility was designed and constructed with the purpose of performing high-temperature transient pool boiling quenching experiments for stainless steel (SS) and zirconium (Zr) cylindrical test samples. The fabricated samples have three embedded thermocouples between the inner surface of the rods and the boron nitride (BN) filler material. The focus of this research is to study the effects of liquid subcooling, surface oxidation and surface materials for the prescribed materials on the minimum film boiling temperature, Tmin. The samples were heated to a temperature well above the Tmin (up to 550oC) then plunged vertically in a quiescent pool of subcooled and saturated distilled water. A data acquisition system was used to record the temperature of the embedded thermocouple locations over time. Data reduction was performed by using an inverse heat conduction code (DATARH) to calculate the surface temperature and the corresponding wall heat flux. A visualization study using a high-speed camera was conducted. Additionally, a characterization study using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS) methods was performed to quantify surface conditions. Results indicate that liquid subcooling has a strong influence on Tmin. The visualization study shows a very thin vapor formation around the rod for higher subcooling cases that explains the enhancement in the heat transfer. Also, the surface characterization shows the difference in surface condition of the SS and Zr that leads the vapor bubbles to depart differently in the nucleate boiling regime. Furthermore, the effect of surface oxidation is noticeable in the Zr rod compared to SS rod due to the oxidation kinematic of the substrate material. Finally, it is found that the surface properties have a significant impact on Tmin.

KW - Minimum film boiling temperature

KW - Oxidation

KW - Surface characterizations

KW - Transient pool boiling

KW - Vertical rod

UR - http://www.scopus.com/inward/record.url?scp=85052461627&partnerID=8YFLogxK

M3 - Paper

AN - SCOPUS:85052461627

T2 - 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017

Y2 - 3 September 2017 through 8 September 2017

ER -

An experimental investigation of the effects of surface conditions on pool-boiling heat transfer for various materials

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