Chilton–Colburn J-factor analogy (also known as the ''modified Reynolds analogy''
) is a successful and widely used analogy between
heat
In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is ...
,
momentum, and
mass transfer
Mass transfer is the net movement of mass from one location (usually meaning stream, phase, fraction or component) to another. Mass transfer occurs in many processes, such as absorption, evaporation, drying, precipitation, membrane filtration ...
. The basic mechanisms and mathematics of heat, mass, and momentum transport are essentially the same. Among many analogies (like
Reynolds analogy The Reynolds Analogy is popularly known to relate turbulent momentum and heat transfer.Geankoplis, C.J. ''Transport processes and separation process principles'' (2003), Fourth Edition, p. 475. That is because in a turbulent flow (in a pipe or in a ...
, Prandtl–Taylor analogy) developed to directly relate
heat transfer
Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, ...
coefficients,
mass transfer
Mass transfer is the net movement of mass from one location (usually meaning stream, phase, fraction or component) to another. Mass transfer occurs in many processes, such as absorption, evaporation, drying, precipitation, membrane filtration ...
coefficients, and
friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction:
*Dry friction is a force that opposes the relative lateral motion of ...
factors Chilton and Colburn J-factor analogy proved to be the most accurate.
It is written as follows,
This equation permits the prediction of an unknown transfer coefficient when one of the other coefficients is known. The analogy is valid for fully developed
turbulent flow
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between t ...
in conduits with ''
Re'' > 10000, 0.7 < ''
Pr'' < 160, and tubes where ''L''/''d'' > 60 (the same constraints as the
Sieder–Tate correlation). The wider range of data can be correlated by Friend–Metzner analogy.
Relationship between Heat and Mass;
See also
*
Reynolds analogy The Reynolds Analogy is popularly known to relate turbulent momentum and heat transfer.Geankoplis, C.J. ''Transport processes and separation process principles'' (2003), Fourth Edition, p. 475. That is because in a turbulent flow (in a pipe or in a ...
*
Thomas H. Chilton
References
* Geankoplis, C.J. ''Transport processes and separation process principles'' (2003). Fourth Edition, p. 475.
External links
* Lecture notes on mass transfer coefficients: http://facstaff.cbu.edu/rprice/lectures/mtcoeff.html
Transport phenomena
Analogy
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