Premium
HEAT TRANSFER TO PARTICLES IN CANS WITH END‐OVER‐END ROTATION: INFLUENCE OF PARTICLE SIZE AND CONCENTRATION (%V/V)
Author(s) -
SABLANI S.S.,
RAMASWAMY H.S.
Publication year - 1997
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/j.1745-4530.1997.tb00422.x
Subject(s) - particle (ecology) , particle size , analytical chemistry (journal) , chemistry , heat transfer , rotation (mathematics) , materials science , thermodynamics , thermal conduction , chromatography , composite material , physics , geometry , oceanography , mathematics , geology
The heat transfer coefficients (U and h fp ) associated with particulate fluids in cans were evaluated with suspended Nylon particles, during end‐over‐end rotation. Can rotation speed (10 to 20 rpm), particle diameter (19 to 25 mm) and particle concentration (single particle to 40% v/v) were studied as variables using fluids of two different viscosities (1.0 × 10 −6 and 1 × 10 −4 m 2 /s). Particle transient temperatures were measured by placing a flexible thermocouple attached to the particle, allowing particle motion inside the can. Transient heat conduction equations for a spherical particle with convective boundary condition at fluid‐particle interface were numerically solved to obtain h fp . An overall heat balance equation was solved to obtain U. The h fp values varied from 170 to 1165 W/m 2 .K with oil and 175 to 1550 W/m 2 .K with water depending upon process conditions. The U values varied from 110 to 220 W/m 2 .K with oil and 480 to 800 W/m 2 .K with water. The h fp increased 10 to 60% with decreasing particle diameter from 25 to 19 mm while it increased about 3 folds as the particle concentration changed from a single particle to 30%. Further increase in panicle concentration to 40% decreased the h fp between 5 and 20% depending upon processing conditions. The effects of particle size and particle concentration on the U were similar to those obtained with h fp with lower magnitudes.