Influence of cryogen spray cooling parameters on the heat extraction rate from a sprayed surface

Emil Karapetian; Guillermo Aguilar; Enrique J. Lavernia; J. Stuart Nelson M.D.

doi:10.1117/12.441252

17 June 2002 Influence of cryogen spray cooling parameters on the heat extraction rate from a sprayed surface

Emil Karapetian, Guillermo Aguilar, Enrique J. Lavernia, J. Stuart Nelson M.D.

Proceedings Volume 4609, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems XII; (2002) https://doi.org/10.1117/12.441252
Event: International Symposium on Biomedical Optics, 2002, San Jose, CA, United States

Abstract

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.

Citation Download Citation

Emil Karapetian, Guillermo Aguilar, Enrique J. Lavernia, and J. Stuart Nelson M.D. "Influence of cryogen spray cooling parameters on the heat extraction rate from a sprayed surface", Proc. SPIE 4609, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems XII, (17 June 2002); https://doi.org/10.1117/12.441252

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available