Influence of nozzle‐to‐skin distance in cryogen spray cooling for dermatologic laser surgery

Aguilar, Guillermo; Majaron, Boris; Pope, Karl A.; Svaasand, Lars O.; Lavernia, Enrique J.; Nelson, J. Stuart

doi:10.1002/lsm.1025

Cited by 75 publications

(72 citation statements)

References 16 publications

(30 reference statements)

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“…Due to the small variations in the spray temperature seen in the confines of this study, it is clear that the spray temperature does not heavily influence the heat flux values measured. In fact, earlier studies suggest that lowering the spray temperature by changing the nozzle to substrate distance does not necessarily increase heat flux [5,10].…”

Section: Discussionmentioning

confidence: 99%

“…A custom-made device similar to those reported previously [5,8] was designed and built to measure the maximum heat flux (q max ), and the total heat removed (Q total ) by a 100 ms spurt for all valve/nozzle configurations used in this study. The device consists of a silver disk (3.18 mm diameter, 0.17 mm thickness), thermally insulated by epoxy (k T =.218 W/m-˚K).…”

Section: Heat Flux Measurementsmentioning

confidence: 99%

“…In recent studies, it has been shown that heat flux through the skin can be increased by changing parameters such as nozzle-to-skin distance [5] and nozzle diameter [3,6,7] and/or by depositing cryogen in sequential spurts [8]. These changes influence the fundamental spray parameters such as mass flux, average droplet diameter and velocity, droplet concentration and temperature, which in turn affect the heat flux at the skin surface.…”

Section: Introductionmentioning

confidence: 99%

“…To measure the heat extracted, we used a technique that involves a metallic disk embedded in an insulating epoxy [5,8]. The mass flux for each configuration was computed by measuring the mass of cryogen expelled during timed sprays.…”

Section: Introductionmentioning

confidence: 99%

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<title>Influence of cryogen spray cooling parameters on the heat extraction rate from a sprayed surface</title>

Karapetian¹,

Aguilar²,

Lavernia³

et al. 2002

SPIE Proceedings

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Cryogen spray cooling is used to prevent epidermal thermal damage during port-wine stain laser therapy, despite the limited understanding of the fluid dynamics, thermodynamics, and heat transfer characteristics of cryogen sprays. In recent studies, it has been suggested that the heat flux through human skin could be increased by changing physical parameters such as nozzle-to-skin distance, nozzle diameter, and/or by depositing cryogen in sequential spurts. These changes affect spray parameters such as droplet diameter, velocity, and spray temperature. Therefore, in order to optimize new nozzle designs, it is necessary to explore the influence that these fundamental spray parameters have on heat extraction.In this paper, various valve/nozzle configurations were characterized. A Phase Doppler Particle Analyzer was used to determine the average diameter, velocity, and droplet concentration of various cryogen sprays. The mass flux delivered by each valve/nozzle configuration was also measured, along with the average spray temperature. A custom-made device consisting of an insulated metallic disk was used to measure the heat extracted by different sprays. The results showed that there are significant differences in the heat extracted by the different valve/nozzle configurations. These variations are proportionally influenced by mass fluxes. Strong correlations were also observed between average droplet velocities and heat extraction. These findings indicate that mass flux has a dominant effect on heat extraction from human skin during cryogen spray cooling. It is also apparent that kinetic and thermal energies are other parameters to be considered when optimizing heat extraction.

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Section: Discussionmentioning

confidence: 99%

Section: Heat Flux Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

<title>Influence of cryogen spray cooling parameters on the heat extraction rate from a sprayed surface</title>

Karapetian¹,

Aguilar²,

Lavernia³

et al. 2002

SPIE Proceedings

Self Cite

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“…The CSC process uses spray cooling to cool a human's skin while undergoing some types of laser surgery [8]. Somewhat recently, it has been used for high power density electronics cooling such as laser diodes, power supplies, power converters, electric motors, motor drives, wide band-gap (WBG) semiconductors, computer mainframes, and aviation/automotive electronics.…”

Section: Applicationsmentioning

confidence: 99%

Centrifuge Testing of a Partially-Confined FC-72 Spray

Elston¹,

Yerkes²,

Fleming³

et al. 2006

SAE Technical Paper Series

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information AFRL-PR-WP-TP-2007-209 SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING AGENCY ACRONYM(S) AFRL-PR-WP ABSTRACTThe effects of elevated acceleration fields on spray cooling heat transfer are discussed in this paper. Spray cooling has proven to be one of the most efficient methods of heat removal. This technology is being transitioned into more advanced applications, such as fighter aircraft that must withstand a wide range of variable acceleration-induced body forces. Heat transfer associated with closed-loop spray cooling will be affected by acceleration body forces, the extent of which is not yet known. To test these various effects, an eight-foot-diameter centrifuge table will be outfitted with a spray cooling system to test for the effects associated with elevated gravity. ABSTRACTThe effects of elevated acceleration fields on spray cooling heat transfer are discussed in this paper. Spray cooling has proven to be one of the most efficient methods of heat removal. This technology is being transitioned into more advanced applications, such as fighter aircraft that must withstand a wide range of variable acceleration-induced body forces. Heat transfer associated with closed-loop spray cooling will be affected by acceleration body forces, the extent of which is not yet known. To test these various effects, an eightfoot-diameter centrifuge table will be outfitted with a spray cooling system to test for the effects associated with elevated gravity.

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Effects of Cryogen Spray Cooling and High Radiant Exposures on Selective Vascular Injury During Laser Irradiation of Human Skin

Tunnell¹,

Chang²,

Johnston³

et al. 2003

Arch Dermatol

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Influence of nozzle‐to‐skin distance in cryogen spray cooling for dermatologic laser surgery

Abstract: Sprayed areas and heat extraction efficiencies produced by current commercial nozzles may be significantly modified by varying the distance between the nozzle and the sprayed surface.

Cited by 75 publications

References 16 publications

<title>Influence of cryogen spray cooling parameters on the heat extraction rate from a sprayed surface</title>

<title>Influence of cryogen spray cooling parameters on the heat extraction rate from a sprayed surface</title>

Centrifuge Testing of a Partially-Confined FC-72 Spray

Effects of Cryogen Spray Cooling and High Radiant Exposures on Selective Vascular Injury During Laser Irradiation of Human Skin

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