Effect of Rheological Properties of Product on Fouling in Falling Film Evaporators.
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| Title: | Effect of Rheological Properties of Product on Fouling in Falling Film Evaporators. |
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| Authors: | Hashemizadeh, Iman1 (AUTHOR) iman.hashemizadeh@fonterra.com, Zare, Davoud1 (AUTHOR), Brown, Colin1 (AUTHOR) |
| Source: | Heat Transfer Engineering. 2026, Vol. 47 Issue 11/12, p1049-1054. 6p. |
| Subject Terms: | *Fouling, *Non-Newtonian fluids, *Food industry, *Heat transfer, *Viscosity, *Rheology, *Evaporators |
| Abstract: | Preventing excessive fouling of falling film evaporators is achieved by controlling the product mass flow rates per unit circumference of evaporator tubes to avoid film break-up. This is referred to as the minimum wetting rate. Prior research has calculated the minimum wetting rate as the balance between the fluid pressures acting downwards and the opposing combined upward forces. The balance of forces is strongly influenced by the viscosity of liquid. Models proposed in literature have tended to utilize constant Newtonian viscosity, however this is not applicable for many foods including concentrated milk where the fluid behavior is non-Newtonian at higher solid contents. To address this challenge, our study extended the previous work to apply for non-Newtonian fluids. The predictions from these calculations were experimentally evaluated using a pilot scale evaporator apparatus where heat transfer data was used to infer the evidence of evaporator fouling. No excessive evaporator fouling was observed over 7.5 h of operation suggesting that the evaporator tube was completely covered when the wetting rate exceeded the calculated minimum threshold from our model. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
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| Abstract: | Preventing excessive fouling of falling film evaporators is achieved by controlling the product mass flow rates per unit circumference of evaporator tubes to avoid film break-up. This is referred to as the minimum wetting rate. Prior research has calculated the minimum wetting rate as the balance between the fluid pressures acting downwards and the opposing combined upward forces. The balance of forces is strongly influenced by the viscosity of liquid. Models proposed in literature have tended to utilize constant Newtonian viscosity, however this is not applicable for many foods including concentrated milk where the fluid behavior is non-Newtonian at higher solid contents. To address this challenge, our study extended the previous work to apply for non-Newtonian fluids. The predictions from these calculations were experimentally evaluated using a pilot scale evaporator apparatus where heat transfer data was used to infer the evidence of evaporator fouling. No excessive evaporator fouling was observed over 7.5 h of operation suggesting that the evaporator tube was completely covered when the wetting rate exceeded the calculated minimum threshold from our model. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 01457632 |
| DOI: | 10.1080/01457632.2025.2502225 |
