A 3D coupled model of turbulent forced convection and diffusion for heat and mass transfer in a bioleaching process

Zambra, Carlos E.; Muñoz, José F.; Moraga, Nelson O.

doi:10.1016/j.ijheatmasstransfer.2015.01.135

Cited by 9 publications

(3 citation statements)

References 18 publications

(25 reference statements)

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“…The integrals were calculated using the trapezoidal method of second-order accuracy. Thus, the relative error (RE) at time t is defined by the following equation (Zambra et al., 2015):RE=true|∫y=0y=maxftrue(x,ytrue)t,FVMⅆy−∫y=0y=maxftrue(x,ytrue)t,exⅆytrue|true|∫y=0y=maxftrue(x,ytrue)t,exⅆytrue|.…”

Section: Methodsmentioning

confidence: 99%

Simulation of mass transfer in hollow fiber used for concentration of juices by osmotic distillation

Zambra

2019

Heliyon

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A bi-dimensional diffusion mathematical model is proposed to study mass transfer in hollow fiber used for the concentration of juices by osmotic distillation (OD). The mathematical model was solved using the Finite Volume Method (FVM). The mass fraction at the boundaries was calculated by using the Functional-group Activity Coefficients (UNIFAC) method for the juice and by the Analytical Solutions Of Groups (ASOG) method for the brine. Calculated results were compared to an analytical solution for a case of mass diffusion in a cylinder with mass flow boundary condition. An algorithm to find the effective diffusion coefficient of gas through the membrane is proposed. To show its usefulness, different velocities were applied over the fiber surface to study the bi-dimensional effects that this velocity field has on the mass transfer inside the fiber. The results showed a maximum error of 5.6% when compared to experimental results.

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Section: Methodsmentioning

confidence: 99%

Simulation of mass transfer in hollow fiber used for concentration of juices by osmotic distillation

Zambra

2019

Heliyon

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“…The sensitivities from the initial states to the output (S S S yx 0 ) are found from: Coupled CDR equations typically describe the dynamics of post-harvest storage processes. However, these equations are also used in a wide range of other processes that utilise the laws of conservation of heat and mass (see, for instance, Hsieh & Yang, 2010;Vali, Simonson, Besant, & Mahmood, 2009;Zambra, Munoz, & Moraga, 2015). In the porous medium of a bulk food-storage facility, interaction between the product and the air induces the coupling between the CDR equations that describe temperature in the air and in the food product.…”

Section: Non-linear 1d Cdr Sensitivity Fieldsmentioning

confidence: 99%

Controllability and observability of 2D thermal flow in bulk storage facilities using sensitivity fields

Grubben

Keesman

2017

International Journal of Control

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To control and observe spatially distributed thermal flow systems, the controllable field and observable field around the actuator and sensor are of interest, respectively. For spatially distributed systems, the classical systems theoretical concepts of controllability and observability are, in general, difficult to apply. In this study, sensitivity fields were used to analyse the behaviour from input to state and from initial state to output. For the analysis of controllability and observability, a large-scale, bulk storage facility with coupled thermal flow of air and agro-products was used. Analysis of this system using the classical systems theory results in controllability and observability results that are dependent on the step size of the spatially discretised system. Due to matrix multiplications, inaccurate results are calculated if the step size is too small. Our findings indicate that input-state and initial-state output sensitivity fields provide sufficient information about the controllability and observability of large coupled spatially distributed systems, using finite-dimensional state space representation with small discretisation steps.

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“…Coupled convection-diffusion-reaction equations typically describe the dynamics of postharvest storage processes. However, these equations are also used in a wide range of other processes that utilise the laws of conservation of heat and mass (see, for instance, Vali et al, 2009;Hsieh and Yang, 2010;Zambra et al, 2015). In the porous medium of a bulk food-storage facility, interaction between the product and the air induces the coupling between the convection-diffusion-reaction equations that describe temperature in the air and in the food product.…”

Section: In-and Output Sensitivities Of 2d Coupled Thermal Flow In Bumentioning

confidence: 99%

Modelling ventilated potato bulk storage facilities

Grubben

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The potential of improving the conventional potato bulk storage process is accelerated through this thesis by defining, calibrating and validating a spatially distributed storage model that includes multiple quality aspects. The calibration and validation was performed using large-scale experimental data. Potatoes are one of the world's staple foods. While their crops are seasonal, the demand for them is continuous, resulting in the need to store them and keep them well. As the climate conditions surrounding stored potatoes influence potato quality and vice versa, climate control is an efficient way to influence product quality. Potato storage facilities therefore widely use climate control to limit losses during storage. However, good climate conditions do not automatically guarantee a high-quality end product. At present, climate control in conventional storage facilities is based on rules of thumb, gathered by trial and error and through experiments that mainly can only be evaluated once a year. Because of that, and also as a result of the increased range of potato varieties, each with its own properties, as well as of changes in growth, climate and storage conditions, finding the optimal storage climate conditions is an art and science that advances very slowly. The use of product quality control in addition to climate control was already proposed in the early 2000s, but is still not yet widely applied in commercial storage facilities due to a gap in insights into particularly the spatial distribution of how multiple quality aspects develop during storage. The aim of this research was to fill a vital gap in the knowledge on how climate and the product quality development of potatoes interact during bulk storage, by developing a spatially distributed mathematical storage model, analysing the simulation results, and evaluating these with respect to experimental data from industrial bulk storage facilities. In this thesis in particular the temperature, moisture content and reducing sugar content interaction and development in a conventional bulk storage, with a cellar and perforated floor and ventilation capacities of 100-150 cube air per cube product per hour, is evaluated and theoretically improved. A 2-D and 1-D climate-product quality model for the evaluation of the complete bulk storage process are presented in this thesis. This study particularly concerns conventional bulk storage facilities for frying potatoes, but the research is also of value for different types of storage facilities and different agro-materials.

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A 3D coupled model of turbulent forced convection and diffusion for heat and mass transfer in a bioleaching process

Cited by 9 publications

References 18 publications

Simulation of mass transfer in hollow fiber used for concentration of juices by osmotic distillation

Simulation of mass transfer in hollow fiber used for concentration of juices by osmotic distillation

Controllability and observability of 2D thermal flow in bulk storage facilities using sensitivity fields

Modelling ventilated potato bulk storage facilities

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