Tray Geometry Research Articles

Effects of semi‐rigid plastic tray geometry on quality characteristics of a retort food simulant

AbstractThe present study aims to investigate how the geometric shapes of semi‐rigid plastic trays impact the quality characteristics of a retort processed food simulant. Initially, oval, triangular, rectangular, and round‐shaped plastic trays with a tomato‐based food simulant were subjected to retorting at rotational speeds of 6 and 11 revolutions per minute (RPM), and various food quality attributes were assessed. At 6 RPM, triangle‐shaped and round‐shaped trays exhibited a significantly greater reduction (p < 0.05) in ascorbic acid (AA) content compared to oval or rectangular‐shaped trays. Furthermore, there were no significant differences (p > 0.05) in lycopene and hydroxymethylfurfural (HMF) content change from control among the different tray shapes at 6 RPM. However, hexanal content change was found to be greater in rectangular‐shaped trays than in oval‐shaped trays, while no significant difference was observed between triangular and round‐shaped trays. Both triangular and rectangular‐shaped trays showed a substantially greater (p < 0.05) total color difference (ΔE) compared to other shapes. This data suggests the presence of a temperature gradient in the food simulant influenced by the tray's shape. At 11 RPM, oval and round‐shaped trays showed a significant reduction in AA content, while rectangular‐shaped trays exhibited higher lycopene levels compared to oval and round trays. There was an increase in HMF response from control across all tray shapes; however, differentiation between shapes was not significant (p > 0.05), while both triangle and round‐shaped trays had elevated hexanal content as compared to oval‐shaped trays (p < 0.05). Oval, round, and triangle‐shaped trays all exhibited a greater ΔE than rectangular‐shaped trays. In summary, oval and round‐shaped trays exhibited a more pronounced change in AA content at 11 RPM, indicating a faster temperature equilibration. In contrast, triangle and rectangular‐shaped trays displayed elevated total color differences at 6 RPM, which may suggest the presence of a temperature gradient leading to uneven heating due to their respective shapes.Practical applicationsThis information would be applicable to new food products designed for thermal treatment in which the packaging shape could be manipulated to not only fit infrastructure requirements (packaging equipment, processing equipment, distribution devices) but also help support heat penetration at an optimal rate. Depending on product type and makeup, this approach may hold some value to the product developer whose product will be packaged in semi‐rigid plastic containers.

Hybrid modeling of drop breakage in pulsed sieve tray extraction columns

Accurate models for pulsed sieve tray extraction columns (PSEs) depend on the correct prediction of the drop diameter to estimate extractive mass transfer across the phase boundary. Phenomenologically, the drop diameter is determined by a balance of drop breakage and coalescence. While for most industrial solvent systems, coalescence plays a minor role; breakage is mostly the dominant phenomenon determining the drop diameter. However, most modeling approaches for drop breakage in PSEs are characterized by a trade-off between a broad validity range and good prediction accuracy. To overcome this limitation, we developed a hybrid breakage model for drop breakage in PSEs in which a physical-empirical model basis is enhanced by data-driven parameter estimator models (PEMs). The hybrid model is based on a revised form of Garthe’s breakage model, for which we developed a linear PEM for the model parameters and two data-driven PEMs for dstab and d100, respectively. The hybrid breakage model was validated on 743 experimental data sets and evaluated based on the pull metric. In a sensitivity analysis, the model correctly predicted the breakage probability over a wide range of solvent properties, operating conditions, and sieve tray geometries. In future studies, the hybrid breakage model can be incorporated into extraction column models without an initial parametrization.

Revamping of crude distillation unit for enhancement of processing capacity and LPG extraction through steady state simulation modeling

The scope of this work covers the debottlenecking of operational constraints for increasing the processing capacity of crude distillation unit and LPG extraction from crude oil. Simulation modeling on Aspen HYSY V7.1 is used for thoroughly investigating and evaluation of retrofit alternatives. Design and operations data of a crude distillation unit at Attock Refinery Limited is used as a case study. Capacity expansion through the addition or rearranging of circulating reflux/Pump-around is selected among the various available revamp alternates like addition of Pre-flash columns, tray geometry and hydraulics etc. Then crude distillation unit is revamped for maximum possible expansion in processing capacity by re-arranging of Pump-around circuits. Pump-around balances re-arranged based on specific crude oil operating blend. Some modifications are also proposed in stabilizer section of the crude distillation unit to enhance LPG extraction from crude oil and finally crude distillation unit simulated for revamped processing capacity with re-arranged pump-around circuits and suggested modifications in stabilizer section. The results of Simulation Modeling validate propose modifications for revamping of processing capacity and LPG extraction.

Sensitivity Analysis of Open-Top Cartons in Terms of Compressive Strength Capacity.

Trays in which fruit and vegetables are transported over vast distances are not only stored in extreme climatic conditions but are also subjected to long-term loads. Therefore, it is very important to design them correctly and select the optimal raw material for their production. Geometric parameters that define the shape of the packaging may also be optimized in the design process. In this work, in order to select the most important parameters that affect the load capacity of a tray, sensitivity analysis was used. A sensitivity analysis is often the first step in the process of building artificial-intelligence-based surrogates. In the present work, using the example of a specific tray's geometry, the selection of starting parameters was carried out in the first step, based on the Latin hypercube sampling method. In the next step, local sensitivity analyses were performed at twenty selected starting points of the seventeen-dimensional space of the selected parameters. Based on the obtained results, it was possible to select the parameters that have a significant impact on the load capacity of the tray in the box compression test and whose influence is negligible or insignificant.

CFD Simulations of Fire Propagation in Horizontal Cable Trays Using a Pyrolysis Model with Stochastically Determined Geometry

In this paper, a pyrolysis model for a PVC cable is constructed using results from thermogravimetric analysis, microscale combustion calorimeter and cone calorimeter experiments. The pyrolysis model is used to simulate fire propagation in horizontal cable trays. The simulated arrangement corresponds to a cable tray fire experiment from OECD PRISME 2 project. As laying the cables loosely along the horizontal trays is a random process, a novel stochastic method is developed for making the simplified cable tray geometries for the computational fluid dynamics model. In addition, as the simplified cable tray geometry has significantly smaller surface area than a real tray full of cables, the surface area was parametrically adjusted. In contrast to most of the earlier published numerical approaches for simulating cable tray fires, the presented approach does not use empirical correlations for predicting fire propagation and does not require any results from full-scale experiments for calibrating the model. The simulation results are compared to experimental results in terms of heat release rate, mass loss, tray ignition times and lateral flame spread rates. The maximum heat release rate was overpredicted by 8% on average.

Experimental investigation towards the transport‐optimized design of peelable polymer tray packaging

Demands of peelable food packaging require a design to ensure both ease of usage as well as sturdiness in order to endure multiple loadings during transport. To aid the design processes in addressing these criteria, this paper aims to present factors influencing the closure safety and damaging behaviour during transport. Regarding this, we first present a methodology for the experimental investigation of transport safety, based on a substitute test, which aims to reflect the effects of vertical impact during transport. To achieve these conditions, we propose both the construction of a test rig and subsequent evaluation parameters to assess the damage of the packaging's sealed seam. Following that, the specific parameters of the experimental study based on the proposed method are presented. These include strength of a sealed seam, the thicknesses of used polymer films and the tray geometry itself. The results of this study and limitations are addressed in the final chapter, whereby first qualitative influences of the parameters become assessable, along with suggestions for further scientific work on the subject matter.

CFD Modeling to Predict Mass Transfer in Multicomponent Mixtures

Abstract A novel three-dimensional computational fluid dynamics mass transfer (CMT) model in Eulerian–Eulerian frame work is deploys for investigating the concentration profiles, and trays efficiencies in multicomponent distillation columns. The proposed model is based on Maxwell Stefan equations, and CFD was employed as a powerful tool to model the hydrodynamics and mass transfer. The two phases are modelled as two interpenetrating phases with interphase momentum, heat and mass transfer. The Closure model is developed for mass interphase transfer rate in ternary mixtures. The predictability of the mass transfer behaviours of multicomponent can result in a more efficient and predictable design of distillation trays. Two non-ideal ternary mixtures were studied. The tray geometry and operating conditions are based on the experimental works of Kalbassi and the composition profiles, tray efficiencies, and point efficiencies of mixtures were presented. The obtained results were confirmed by the experimental data. The results indicate that the values of individual component tray efficiencies and point efficiencies for these multicomponent systems were considerably different which confirm the interactive nature of the mass transfer in multicomponent mixtures. These mixtures also illustrated different point efficiencies across the tray because of the composition dependency of these mixtures. The average relative error for the prediction of efficiencies is about 8 %, which indicates the accuracy of the model.

Evolutional computational fluid dynamics analyses of reactive distillation columns for methyl acetate production process

The hydrodynamics of non-reactive and reactive distillation sieve tray columns are analyzed in this study. The first mentioned task was performed in order to verify the accuracy of Computational Fluid Dynamics (CFD) simulation in modeling the flow behavior of a sieve tray system. For the reactive distillation system, the studies were performed for the 25th reactive tray in the methyl acetate (MeAc) production process. Aspen Plus V9.0 simulation was carried out to determine the clear liquid height on the tray as a function of tray geometry and operating condition. The transient vapor-liquid hydrodynamics on the 25th reactive tray was simulated using CFD techniques involving the turbulence-chemistry interaction (TCI) effects. The predicted chemical products in liquid and vapor phases by Aspen Plus and CFD are of reasonable agreement. Furthermore, the CFD results can deliver more physics in determining localized distributions of the hydrodynamic parameters in the MeAc production process. Information obtained about the location and distribution of the vortex flow can be used to optimize the heat transfer and turbulence mixing.

Effects of Packaging Geometry on Heat Penetration Time in Retortable Semi-Rigid Plastic Trays

Semi-rigid, retortable trays were filled with a food simulate and thermally processed in a water immersion automated batch retort system at rotational speeds of 6 RPM and 11 RPM. Triangle, rectangle, oval, and round trays were evaluated, each having approximately the same overflow capacity. During processing, trays were fixed in place with racks containing one shape per rack. Various rack location combinations were tested to provide processing data for each shape in each rack location. Heat penetration data was gathered using thermocouples located in the geometric center of each tray shape and this data was modeled to determine the slowest heating container. No differences were observed in rack location among tray geometries at either RPM level (P>0.05). The data generated during heat penetration runs was also used to model different retort temperatures and lethality values. A retort temperature of 215°F and a lethality value of 10 showed the highest average sterilization time (P 0.05) than any other shape tray. At a rotational speed of 11 RPM, differences in average process time to reach lethality between tray geometries were insignificant (P>0.05).

Experimental study of two phase flow characteristics on the dual-flow tray

This paper addresses an experimental investigation in the hydrodynamic behavior of a new type of dual-flow fixed valve tray. Water/air system was used at atmospheric pressure and ambient temperature. The dry pressure drop, total pressure drop and clear liquid height were measured and the comparisons between different tray geometry were made. The results show that the total pressure drop and clear liquid height have the same trend, which is increased with the decreased center distance of holes, increased holes diameter and decreased open area. Correlation for clear liquid height is proposed, and the agreement of the experimental and calculated data is demonstrated in the paper.The results show that gas and liquid flow counter-currently through the tray hole area and four main hydrodynamic regimes are distinguished at different gas/liquid load. A characteristic parameter named the fraction of holes passing gas is defined and deduced. The calculated results show that the fraction of holes passing gas is reduced by the decreased center distance of holes and holes diameter, while the increased open area leads to the less fraction.

A Combined Computational Fluid Dynamics and Artificial Neural Networks Model for Distillation Point Efficiency

In this work a CFD-ANN model is developed to give the predictions of sieve tray point efficiency. The main objective has been to find the extent to which CFD can be used in combination with artificial neural network as a prediction tool for efficiencies of industrial trays. The model was tested against a wide range of tray geometries, operating conditions and binary systems of materials. CFD model was applied, as a virtual experiment tool for direct prediction of point efficiencies, using tray geometries and operating conditions for any binary system of liquids. The model results were in agreement to experimental data from literatures, shown that CFD-ANN model can be used as a powerful tool in distillation column design and analysis.

The effect of tray geometry on the sieve tray efficiency

In this research a 3-D two phase CFD model in Eulerian–Eulerian framework was developed to study sieve trays efficiency, hydraulics and mass transfer. To estimate the efficiency of the sieve trays, two trays with similar geometry but unequal hole diameters were used while the effects of the holes and bubbles diameters were observed. The results were compared with the available experimental data for distillation of methanol and n-propanol mixture. Mass transfer coefficients were estimated by the Higbie and surface renewal stretch (SRS) mass transfer models. It has been found that the liquid flow pattern on the tray which had smaller hole diameter is closer to the plug flow pattern and tends to have a larger mass transfer rate. In addition, while comparing the SRS model theory with the Higbie model, it has been found that using the SRS model reduces the sensitivity of the simulation results to the bubble diameters.

Enhancement of Sieve Tray Efficiency using Computational Fluid Dynamics

High degree of competitiveness associated with petroleum leads to the exhaustive search for new technologies that enable greater efficiency in the related processes. A three-dimensional mathematical homogeneous biphasic model was implemented in the commercial code of Computational Fluid Dynamics (CFD), FLUENT package to predict concentration and temperature distributions on sieve trays of distillation columns and good simulation results are obtained. The tray geometries and operating conditions are based on the experimental works of Indian oil corporation limited (R&D). The dispersed gas phase and continuous liquid phase are modelled in the mixture model for two interpenetrating phases with inter phase momentum, heat and mass transfer. The main objective of this study has been to find the extent to which CFD can be used as a prediction tool for real behaviour, and concentration and temperature distributions of sieve trays. The simulation results are shown that CFD is a powerful tool in tray design, analysis and trouble shooting, and can be considered as a new approach for efficiency calculations.

Computational fluid dynamic simulation of MVG tray hydraulics

The flow pattern and hydraulics of a Mini V-Grid valve (MVG) tray is predicted by using computational fluid dynamics simulation. A 3-D CFD model in the Eulerian framework was used. The simulation results for MVG tray are compared with that of sieve tray. The sieve tray geometry and operating conditions are based on the Solari and Bell’s sieve tray [1]. The MVG tray differs from that of Solari and Bell’s sieve tray solely by the difference in design of available openings for the flow of gas. The simulation results show that the clear liquid height and the pressure drop of MVG tray are lower than that of sieve tray whereas the liquid velocity is higher and contacts of phases are good. The simulation results of sieve tray are in agreement with the experimental data of Solari and Bell [1].

Affect of Part Geometry on Wall Features in Rectangular Deep-Drawing Processes Using Finite Element Method

High-quality stamped parts using cost-effective production technique are increasingly required, especially in parts with complex geometry wherein forming defects are easily generated. In this study, the concave and convex wall features were investigated for a stainless steel rectangular tray using the finite element method and related experiments. The concave and convex wall phenomena were theoretically clarified on the basis of stress distribution. The effects of tray geometry were also investigated. Increasing both the rectangle size and depth of tray, together with a decrease in the corner radius, resulted in an increase in concave wall generation. However, the effects of increasing the length or width of the rectangle affecting the concave wall were independent of each other. In addition, the application of a very large depth of tray resulted in a convex feature. The results showed that it is difficult to achieve a straight wall on both the ‘length’ and ‘width’ sides without the use of draw bead. The finite element simulation results showed a reasonable agreement with the experimental results, with reference to the material thickness distribution in both the cases of: absence of the draw bead formation; and presence of the draw-bead formation.

The impact of valve tray geometry on the interfacial area of mass transfer

AbstractThe interfacial area of mass transfer is one of the key parameters in valve tray design, and the valve geometry is the important structural parameter that determines the interfacial area. In this work, the hydrodynamic and mass‐transfer characteristics of three different types of valve trays are investigated. The mechanism of bubbles deformation and breakage in the turbulent dispersion system is theoretically analyzed on the basis of Kolmogoroff's isotropic turbulence hypothesis, and a novel model is proposed to predict the interfacial area. The results show that the simulation results agree well with the experimental data. In contrast to most of the conventional models, the present model is capable of evaluating the effects of valve configuration on the interfacial area. The model is expected to guide effectively the design of valve trays which is widely applied nowadays. © 2008 American Institute of Chemical Engineers AIChE J 2008

고속으로 회전하는 광디스크 드라이브의 공력 소음원 규명 및 소음저감방법

Major noise source in high speed rotating optical disk drives (CD and DVD-ROM) arises due to the high-speed airflow produced from the upper and lower surfaces on the rotating disk. The present paper deals with the experimental approach how to identify the noise source based on the fundamental principles of aeroacoustics and to propose a reduction method of the noise source. The CD-ROM device is composed of disk, window tray, motors at the bottom place and electronic circuit plate also located below the window plate. The window is cut in the tray to read the disk information using the optical device located below the tray and moving linearly from the center of the disk through the end of the disk. All components are possible noise generators. Experimental studies were carried out in the anechoic room with various design modifications, such as tray geometry, window size and hole location on tray, to identify the major aerodynamic noise source and significant reductions of the aerodynamic noise were obtained.

Rigorous Dynamic Simulation of an Industrial Tray Column, Considered Liquid Flow Regime and Efficiency of Trays

A rigorous model is presented for dynamic simulation of an industrial tray column which uses mass and energy balances together with a proper hydraulic equation. Three different liquid flow regimes can be considered in the industrial tray columns which each of them possesses a specific hydraulic equation. The implemented model by recognizing the type of liquid flow regime is able to use the proper hydraulic equation in the computations. Moreover, by calculating the tray efficiency, the effect of tray geometry on the separation performance is investigated. As the result of this study, the open loop response of the industrial tray column is presented after inputting a step change in reflux flow rate.

Efficiencies of Sieve Tray Distillation Columns by CFD Simulation

A 3-D two-fluid CFD model in the Eulerian-Eulerian framework was developed to predict the hydrodynamics and heat and mass transfer of sieve trays. Interaction between the two phases occurs via interphase momentum and heat and mass transfer. The tray geometries are based on the large rectangular tray of Dribika and Biddulph and FRI commercial-scale sieve tray of Yanagi and Sakata. In this work a CFD simulation is developed to give predictions of the fluid flow patterns, hydraulics, and mass transfer efficiency of distillation sieve trays including a downcomer. The main objective has been to find the extent to which CFD can be used as a design and prediction tool for real behavior, concentration and temperature distributions, and efficiencies of industrial trays. Despite the use of simple correlations for closure models, the efficiencies obtained are very close to experimental data. The results show that values of point efficiency vary with position on the tray because of variation of affecting parameters, such as velocities, temperature and concentration gradients, and interfacial area. The simulation results show that CFD can be used as a powerful tool in tray design and analysis, and can be considered as a new approach for efficiency calculations and as a new tool for testing mixing models in both phases. CFD can be used as a “virtual experiment” to simulate tray behavior under operating conditions.

Prediction of Temperature and Concentration Distributions of Distillation Sieve Trays by CFD

A three-dimensional two-fluid computational fluid dynamics (CFD) model is developed to predict concentration and temperature distributions on sieve trays of distillation columns and good simulation results are obtained. The dispersed gas phase and continuous liquid phase are modeled in the Eulerian framework as two interpenetrating phases with interphase momentum, heat and mass transfer. Closure models are developed for interphase transfer terms. The tray geometries and operating conditions are based on the experimental works of Dribika and Biddulph (AIChE. J., 32, 1864, 1986) and Yanagi and Sakata (Ind. Eng. Chem. Process. Des. Dev., 21, 712, 1982). The computational domain is considered to be equal to tray spacing. The main objective of this study has been to find the extent to which CFD can be used as a prediction tool for real behavior, and concentration and temperature distributions of sieve trays. The simulation results are shown that CFD is a powerful tool in tray design, analysis and trouble shooting, and can be considered as a new approach for efficiency calculations.