Heat transfer in pulsed turbulent flow

✍ Scribed by M.H.I. Baird; G.J. Duncan; J.I. Smith; J. Taylor

• Publisher: Elsevier Science
• Year: 1966
• Tongue: English
• Weight: 297 KB
• Volume: 21
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(66)85010-8

✦ Synopsis

Shorter Communications tion should be -I-3.0 per cent for Curve 2 and + I *8 per cent for Curve 3. out this conclusion and conr?rms that the deviation will be greater the wider the distribution in H~'G/~'L or hl/hz.

A general conclusion which can be drawn is that a variation in the group Hk'~/kl~ for mass transfer (or hl/hz for heat transfer) from one point of interface to another will tend to

In Reference [2] it is shown that the occurrence of a con-make the true Koa less than the Kopa predicted from the stant coefficient of mass or heat transfer in one phase coupled classical addition of resistances equation or to make H less than HO for heat transfer. Equation (31) derived by Szekely for fluctuating coefficients with a Gaussian distribution bears a positive deviation from the classical addition equation. A reflects a positive deviation from the c1a.ssica.l addition equa-distribution of surface lifetimes in the second phase then serves to reduce the overall coefficient below that for the tion which is less than that for the constant lifetime case. constant lifetime case. The Danckwerts random surface renewal pattern lowers the overall coefficient sufficiently to provide exact agreement with the classical addition equation. The multiple capacitance model considered by Szekely gives C. JUDSON KING a lifetime distribution in between the constant lifetime and random renewal cases: hence it is logical that the model with a penetration mechanism in the other phase serves to raise the local coefficients in the latter phase. This effect more Department of Chemical Engineering, than offsets the lowering effect of the distribution in Hk'G/kL University of California, or hl/hz for the constant surface lifetime model and results in Berkeley, California.