ISSN Online: 2377-424X
International Heat Transfer Conference 4
FLUID THERMAL DIFFUSIVITY DETERMINATION BY A PULSE TRANSIENT TEMPERATURE TECHNIQUE
Аннотация
A new transient method has been developed for the measurement of fluid thermal diffusivity in which: the fluid boundaries do not affect the measurement,
bulk fluid temperature is not altered, discrimination between conduction and radiation is achieved, and only 1 cc of liquid is used. The system employs a pulsed laser coupled to a microscope to deposit energy in a
local region (~ 40 μm). Microthermocouples (MTC) with junctions of 6-10 μm are used to detect the thermal transient. The MTC signal is amplified and
digitally stored; repetitive analyses enable signal averaging for greater accuracy. Diffusivity determinations at 20 DC, utilizing comparative measurements
with ethylene glycol as the reference fluid, give the following results: Water = 14.3, Ethyl alcohol = 8.5, l-propanol = 8.0 and l-pentanol
= 7.5 (all results × 10−7 square meters/sec).