scholarly journals Enhancement of Heat Transfer Using Taylor Vortices in Thermal Processing for Food Process Intensification

2021 ◽  
Author(s):  
Hayato Masuda

We are witnessing a transition from the traditional to novel processing technologies in the food industry to address the issues regarding energy, environment, food, and water resources. This chapter first introduces the concept of food process intensification based on vortex technologies to all food engineers/researchers. Thereafter, the novel processing methods for starch gelatinization/hydrolysis and heat sterilization based on Taylor–Couette flow are reviewed. In fluid mechanics communities, the Taylor–Couette flow is well-known as a flow between coaxial cylinders with the inner cylinder rotating. Recently, this unique flow has been applied in food processing. In starch processing, enhanced heat transfer through Taylor vortex flow significantly improves gelatinization. In addition, effective and moderate mixing leads to an increase in the reducing sugar yield. In sterilization processing, the enhanced heat transfer also intensifies the thermal destruction of Clostridium botulinum. However, a moderate heat transfer should be ensured because excessive heat transfer also induces thermal destruction of the nutritional components. The Taylor–Couette flow is only an example considered here. There are various flows that intensify the heat/mass transfer and mixing in food processing. It is expected that this chapter will stimulate the development of food processing based on fluid technologies, toward food process intensification.

Author(s):  
S. Gilchrist ◽  
C. Y. Ching ◽  
D. Ewing

An experimental investigation was performed to determine the effect that surface roughness has on the heat transfer in an axial Taylor-Couette flow. The experiments were performed using an inner rotating cylinder in a stationary water jacket for Taylor numbers of 106 to 5×107 and axial Reynolds numbers of 900 to 2100. Experiments were performed for a smooth inner cylinder, a cylinder with two-dimensional rib roughness and a cylinder with three-dimensional cubic protrusions. The heat transfer results for the smooth cylinder were in good agreement with existing experimental data. The change in the Nusselt number was relatively independent of the axial Reynolds number for the cylinder with rib roughness. This result was similar to the smooth wall case but the heat transfer was enhanced by 5% to 40% over the Taylor number range. The Nusselt number for the cylinder with cubic protrusions exhibited an axial Reynolds number dependence. For a low axial Reynolds number of 980, the Nusselt number increased with the Taylor number in a similar way to the other test cylinders. At higher axial Reynolds numbers, the heat transfer was initially independent of the Taylor number before increasing with Taylor number similar to the lower Reynolds number case. In this higher axial Reynolds number case the heat transfer was enhanced by up to 100% at the lowest Taylor number of 1×106 and by approximately 35% at the highest Taylor number of 5×107.


Author(s):  
Vinicius Malatesta ◽  
Vinícius Hagemeyer Chiumento

2021 ◽  
Vol 9 ◽  
Author(s):  
Dong Liu ◽  
◽  
Mohammed Mohammedsalih ◽  
Amponsah-Gyenin Nana Kofi ◽  
Shi-cheng Ding ◽  
...  

Heat transfer enhancement is by far an important component in the design of numerous industrial applications of Taylor-Couette flow including electric motors and particularly rotating machinery. To optimize the performances of these machines, superior knowledge of the fluid flow is vital to better estimate the heat transfer distribution. This study will specifically consider the effect the slit number and width possess on the distribution of turbulent Taylor-Couette flow and the resulting heat transfer correlation in the annulus of two concentric cylinders under varying conditions. A numerical simulation method is intended for the study using varying slit structure parameters of widths (2.5 ≤ w ≤ 7.5) mm and fitted with 6, 9 and 12 number of slits. The slit effect is then investigated under both isotherm and non-isotherm conditions considering the interactions between fluid flow regions in the mainstream area and the annulus. The small-scale vortex that appears in the annulus region improves the heat transferability between the fluid in the annulus and the main region as well as the heat transfer performance of the model with a gradual increase in Reynolds number.


1998 ◽  
Vol 120 (1) ◽  
pp. 65-71 ◽  
Author(s):  
R. Kedia ◽  
M. L. Hunt ◽  
T. Colonius

Numerical simulations have been performed to study the effects of the gravitational and the centrifugal potentials on the stability of heated, incompressible Taylor-Couette flow. The flow is confined between two differentially heated, concentric cylinders, and the inner cylinder is allowed to rotate. The Navier-Stokes equations and the coupled energy equation are solved using a spectral method. To validate the code, comparisons are made with existing linear stability analysis and with experiments. The code is used to calculate the local and average heat transfer coefficients for a fixed Reynolds number (Re = 100) and a range of Grashof numbers. The investigation is primarily restricted to radius ratios 0.5 and 0.7 for fluids with Prandtl number of about 0.7. The variation of the local coefficients of heat transfer on the cylinder surface is investigated, and maps showing different stable states of the flow are presented. Results are also presented in terms of the equivalent conductivity, and show that heat transfer decreases with Grashof number in axisymmetric Taylor vortex flow regime, and increases with Grashof number after the flow becomes nonaxisymmetric.


2021 ◽  
Vol 16 (1) ◽  
pp. JTST0003-JTST0003
Author(s):  
Hiroya MAMORI ◽  
Koji FUKUDOME ◽  
Kohei OGINO ◽  
Naoya FUKUSHIMA ◽  
Makoto YAMAMOTO

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