Measurement of the transient thermal resistance of a sphere in contact with flat surfaces under ambient condition

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20002411

Siu, W W.M.; Lee, S H.K.

Contacting surfaces with loading, which involve heat transfer processes, are common in various engineering systems. Therefore, over the last half-century, extensive works have been done on studying the thermal contact resistance. Nevertheless, there is almost no study on the thermal resistance of sphere, except some works considering spherical surfaces for modeling non-flat engineering surface in contact. However, among most of the heat transfer system, sphere is indeed a common geometry, such as catalytic bed, insulation and powder metallurgy system, and these processes are transient in nature. Therefore, the study of the contact resistances of a sphere and between spheres is indeed significant in this concern. Furthermore, the transient effect on the thermal resistance has to be investigated. By and large, the current typical apparatus, which have been used for measuring contact resistance at steady state condition, may require quite a bit a modification with sophisticated control systems. Therefore, development of the experimental setup was required. Instead of using guard heater and vacuum chamber, this setup makes use of the thermal contact resistance between interface of insulation layers and eliminated natural convection by minimizing the buoyancy to viscous forces ratio. The proposed experimental setup was verified with different tests that the error due to heat loss is often less than 15%. Furthermore, some actual thermal resistance measurements were performed to show the applicability of this setup.

• Research Organization: Hong Kong Univ. of Science and Technology, Kowloon (HK)
• OSTI ID: 20002411
• Report Number(s): CONF-990805--
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
HEAT TRANSFER
INTERFACES
SPHERES
SURFACES
TEST FACILITIES
THERMAL CONDUCTIVITY