A MODEL FOR HEATING of LIQUID‐PARTICLE MIXTURES IN A CONTINUOUS FLOW OHMIC HEATER1

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Abstract
Design of safe thermal processes in a continuous flow ohmic heater requires mathematical model development, since temperature monitoring of particles in continuous flow is not presently possible. A mathematical model previously developed and verified for a static heater was modified to predict temperatures of fluids and particles within a continuous heater with high particle concentration suspensions. Results for constant voltage simulations indicate that the presence of large populations of low electrical conductivity particles results in slow heating of the entire mixture rather than a single phase alone. In all these cases, particles tend to heat faster than the liquid. However, if isolated low‐conductivity particles enter the system, the danger of underprocessing exists; hence particle conductivity is a critical control point. Simulations also indicate the role played by residence time distribution and liquid‐particle heat transfer coefficients in the above cases.