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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

HEAT TRANSFER CHARACTERISTICS OF MULTI-PULSED CRYOGEN SPRAY COOLING FOR LASER LIPOLYSIS

Get access (open in a dialog) DOI: 10.1615/IHTC16.rac.022308
pages 8463-8470

摘要

As an effective noninvasive or minimally invasive treatment, laser lipolysis has great potential for reduce obesity based on the principle of laser photothermolysis or organisms photomodulation. However, skin burns or blisters and no effective skin tissue cold protection method limited the dosage of laser energy and treatment effect. Learn from cryogen spray cooling for port wine stain laser surgery, a novel multi-pulsed cryogen spray cooling for laser lipolysis was proposed to protect skin tissue from thermal damage. Thus, we need investigate temperature contribution and heat transfer in deeper epidermis and dermis tissue. The surface heat transfer dynamics exposed continuous and multi-pulsed cryogen spray cooling using R134a was investigated by measure spray center temperature on the surface and 1mm below surface of skin phantom. At the depth of 1mm below skin phantom surface, the multi-pulsed spray with pulse width 30ms could lead to the maximum temperature drop of 28 °C, which is higher by 11 °C than that of a 2s continuous spray. Besides, the multi-pulsed spray cooling could remove far more heat from the substrate comparing to the continuous spray with less at the same total spray duration. For the multi-pulsed spray, the pulse width, duty cycle, and spray times have important effect on the heat transfer characteristics. In the case of same pulse width and spray times, there is an optimal duty cycle (0.007) causing a lowest minimum temperature inside the substrate. This newly proposed cooling method can not only improve the cooling efficiency but also reduce the usage of cooling agent (cryogen), being of great potential in the application of laser lipolysis.