Inlet Gate Research Articles

DEVELOPING AND TESTING AN AIR FLOW DISTRIBUTOR OF SOLAR DRYER FOR DRYING MORINGA OLEIFERA IN ARID CLIMATE

This study was aimed to investigate an air-flow distributer of a solar dryer. This study was contained two factors: First, the air outlet throttle (three angles, 30°, 60°, and 90°). Second, the design of the air inlet with three levels (new design (I2), without (I1), and half-opening air inlet gate of the new design (I3)). The results show significant effects on these parameters, where the highest efficiency (51.7%) was obtained at (I1) and (30°) angles. While the temperature changes between the inlet and outlet had a significant effect on the pressure difference, the pressure difference increased, reaching (1.65 Pa). Also, the drying rate was affected by the temperature and the amount of air entering the dryer. The highest drying rate gave (0.165 kg/h) when used the air discharge angle (30°) with the (I3), where this increased the temperatures of the air in the dryer reduced the air entering.

A Control Program for Hydropower Operation Based on Minimizing the Principal Stress Values on the Dam Body: Mosul Dam Case Study

This study examines the vibrations produced by hydropower operations to improve embankment dam safety. This study consists of two parts: In the first part, ANSYS-CFX was used to generate a three-dimensional (3-D) finite volume (FV) model to simulate a vertical Francis turbine unit in the Mosul hydropower plant. The pressure pattern result of the turbine model was transformed into the dam body to show how the turbine unit's operation affects the dam's stability. The upstream reservoir conditions, various flow rates, and fully open inlet gates were considered. In the second part of this study, a 3-D FE Mosul dam model was simulated using an ANSYS program. The operational turbine model's water pressure pattern is conveyed to the dam's turbine-shared zone. The maximal and minimal upstream reservoir water levels were investigated. A control program was created depending on the principle stress model results collected from the operation of the hydropower plant with the minimum principal stress on the dam body. This research suggests an enhanced turbine operating system, reducing stress on the dam body and increasing dam operation life.

Manufacturing routes of vacuum assisted resin infusion: Numerical investigation

The vacuum assisted resin infusion (VARI) process is a cost-effective technique for manufacturing lightweight large complex composite components. It belongs to the liquid composite molding (LCM) family. In this process, a fibrous preform is placed into a mold cavity, and covered by a vacuum bag, then a sealant tape is used to adhere it to the mold in order to avoid air-resin leakage. A vacuum pump is used to evacuate the air from the closed cavity which leads to compact the fabric preform. The inlet gate is opened and resin impregnates the preform under atmospheric pressure. Based on the tripping of compaction and resin infusion phases, several manufacturing routes manifest and have influence on the process time, resin pressure distribution and preform thickness uniformity. In this paper, a numerical simulation, based on the finite difference method, is conducted to investigate the effect of four major manufacturing routes of VARI process on the aforementioned parameters. The obtained results reveal that the merging of the air vacuuming and resin infusion phases has no mentioned effect on the reduction of the process time. While, the fourth manufacturing route, where the resin injection precedes vacuuming phase, is the best practice of vacuum assisted resin infusion process. In its optimum scenario, this route can reduce the process time with 19.9% as compared to the optimum scenario of the first manufacturing route.

FEM Simulations for the Optimization of the Inlet Gate System in Rapid Investment Casting Process for the Realization of Heat Exchangers

Over the last decades, additive manufacturing (AM) has become the principal production technology for prototypes and components with high added value. In the production of metallic parts, AM allows producing complex geometry with a single process. Also, AM admits a joining of elements that could not be realized with traditional methods. In addition, AM allows the manufacturing of components that could not be realized using other types of processes like reticular structures in heat exchangers. A solid mold investment casting that uses printed patterns overcomes typical limitations of additive processes such as expensive machinery and challenging process parameter settings. Indeed, rapid investment casting provides for a foundry epoxy pattern reproducing the component to exploit in the lost wax casting process. In this paper, aluminium radiators with flat heat pipes seamlessly connected with a cellular structure were conceived and produced. This paper aims at defining and investigating the principal foundry parameters to achieve a defect-free heat exchanger. For this purpose, different device CAD models were designed, considering four pipes’ thickness and length. Finite element method numerical simulations were performed to optimize the design of the casting process. Three different gate configurations were investigated for each length. The numerical investigations led to the definition of a castability range depending on flat heat pipes geometry and casting parameters. The optimal gate configuration was applied in the realization of AM patterns and casting processes

Evaluating the performances of a flexible mechanism of water diversion: application on a northern Italy gravity-driven irrigation channel

Improving the management of irrigation schemes is a priority in the Mediterranean countries of the EU to achieve the objectives of the Water Framework Directive 2000/60EC. In the case of schemes based on open-channel networks for water conveyance and delivery, a limitation to the management efficiency is the huge number of gates that need to be controlled and regulated manually to adapt the flow to the actual irrigation water demand. Automated and coordinated gate regulation of large irrigation schemes has been successfully implemented in some areas of the world (e.g., NSW, Australia), but it implies huge public investments that are often unavailable. Opposite to this top–down approach, the Lombardy region (the largest irrigated region in the EU) has explored an approach based on funding small projects, which should demonstrate the potential of innovation in irrigation practice and foster the expansion of the most effective measures. In this paper, we analyze the effects of one of these projects, consisting in the substitution of a manual gate, controlling the supply of irrigation to a 150 ha irrigation district, with an automated, remotely controlled gate. Nine years of daily flow measurements at the district inlet, provided by the irrigation consortium that manages the gate, were compared with the rigid flow regulation that was applied when the inlet gate was manually regulated and with the irrigation water requirements simulated with a distributed agro-hydrological model widely used in the region for irrigation accounting and planning. The results show that the flexible regulation allowed by the new gate provided an average water saving of 12,000 m3/ha/year compared to the rigid regulation system. A further, though smaller, margin of improvement of 5000 m3/ha/year can be achieved with an optimal regulation that follows exactly the crop water requirements. A further interesting empirical evidence is that the simulation model fits very well the irrigation water requirements of the district using only easily accessible meteorological input data, without exploiting any information from ground or remote sensors to update soil moisture or crop developments during the season. This indicates that it could be effectively used, with very limited costs and effort, to support and improve the gate management. Finally, a preliminary economic analysis shows that the cost of the gate installation is sustainable, but the upscaling of this type of intervention to larger areas requires the support of public funding to cover approximately half of the cost of investment needed for the networking infrastructures.

A Dimensionless Characteristic Number for Process Selection and Mold Design in Composites Manufacturing: Part I—Theory

The present article introduces a dimensionless number devised to assist composite engineers in the fabrication of continuous fiber composites by Liquid Composite Molding (LCM), i.e., by injecting a liquid polymer resin through a fibrous reinforcement contained in a closed mold. This dimensionless number is calculated by integrating the ratio of the injection pressure to the liquid viscosity over the cavity filling time. It is hereby called the “injectability number” and provides an evaluation of the difficulty to inject a liquid into a porous material for a given part geometry, permeability distribution, and position of the inlet gate. The theoretical aspects behind this new concept are analyzed in Part I of the article, which demonstrates the invariance of the injectability number with respect to process parameters like constant and varying injection pressure or flow rate. Part I also details how process engineers can use the injectability number to address challenges in composite fabrication, such as process selection, mold design, and parameter optimization. Thanks to the injectability number, the optimal position of the inlet gate can be assessed and injection parameters scaled to speed up mold design. Part II of the article completes the demonstration of the novel concept by applying it to a series of LCM process examples of increasing complexity.

Estudio de la dinámica sedimentaria de la Laguna costera del Sur de Túnez (Túnez, Mar Mediterráneo)

La laguna sur de Túnez, una laguna costera mediterránea poco profunda, se sometió a importantes trabajos de restauración durante el período 1998-2001, lo que ha llevado a cambios estructurales y funcionales de este ecosistema costero. En este trabajo se presenta un estudio integral de dinámica sedimentaria basado en datos hidrodinámicos, análisis granulométrico, mineralogía y evaluación de impacto. El proyecto de restauración, especialmente el establecimiento de la puerta de entrada de los canales de Rades y Túnez, impuso una dirección de flujo de agua este-oeste controlando la clasificación local de sedimentos. El análisis de tamaño de grano del sedimento superficial muestra que el fondo de la laguna está revestido por sedimentos finos (

Multiphase Fluid Flow in Porous-Fibrous Media: Fundamentals, Mathematical Modeling and Applications on Polymeric Composites Manufacturing

This work provides information about polymer composite manufacturing by using liquid composite material molding, with particular reference to resin transfer molding process (RTM). Herein, several topics related to porous media, fluid flow, mathematical modeling, computational methods, composite manufacturing and industrial applications were presented. Simulation of resin flow into a fibrous (reinforcement) inserted in a parallelepiped mold has been performed, using the Ansys FLUENT® software, and different results of resin volumetric fraction, stream lines and pressure distribution inside the mold, and volumetric fraction always flow rate (inlet and outlet gates) of the resin, as a function of filling time, have been presented and discussed.

Experimental Assessment of Hydrocyclones with two Inlet (Feed) Gates

Hydrocyclone is a device to separate sediments in the water Gravel and sand particles are separated based on the specific weight of the suspended particles in the water by the ratio of their <a title="Centripetal force" href="https://en.wikipedia.org/wiki/Centripetal_force">centripetal force</a> to fluid resistance. Generally, hydrocyclone includes inlet (feed) and outlet flow gates. In this paper, one of the hydrocyclone which is in the Wastewater Treatment Plant of Mashhad has been investigated with respect to rising of the number of inlet flow gates. In other words, water enters to hydrocyclone with two inlets which have made by welding and cutting operations. Results of this research show that the device efficiency has been enhanced 77 percent in sediment removal and the shear limit has been decreased 15 percent by increasing the number of the inlet gates. Assessments indicate the local temperature is not effective in the rate of particle removal in hydrocyclone.

Sistem Pengatur Irigasi Sawah Menggunakan Metode Irigasi Alternate Wetting and Drying Berbasis Teknologi Internet of Things

Rice is the staple food of the majority of Indonesians and most of the population work as farmers. However, the amount of rice produced are still insufficient. To meet the rice needs for the society, it should increase the amount of rice production by focusing on rice field quality such as the water level rice fields. In this study a prototype rice field irrigation system is designed using AWD irrigation method by regulating open activation and closing the inlet gate and exit gate based on the age of paddy which are calculated using RTC and the height of paddy water measured using ultrasonic sensors. The system also designed to receive input from the age of paddy and deactivate the system from the mobile application through the ESP8266 module. Test results from this system can measure water level with accuracy of 95.68% and read real-time time with 98.67% accuracy. The servo motor NFC DS04 works to open the door with a duration of 60 seconds and closes the door with a duration of 56 seconds. The paddy irrigation regulating system can regulate the water level with a success percentage of 81.48%. The system can receive input and deactivate the system with a percentage of success of 70%.

Molding of Polymeric Composite Reinforced with Glass Fiber and Ceramic Inserts: Mathematical Modeling and Simulation

This work provides a numerical study of a polymer composite manufacturing by using liquid composite material molding. Simulation of resin flow into a porous media comprising fiber perform (reinforcement) inserted in a mold with preallocated ceramic inserts has been performed, using the Ansys FLUENT® software. Results of resin volumetric fraction, stream lines and pressure distribution inside the mold, and mass flow rate (inlet and outlet gates) of the resin, as a function of filling time, have been presented and discussed. Results show that the number of inserts affects the filling time whereas the distance between them has no influence in a process.

Response of unconfined turbidity current to relay‐ramp topography: insights from process‐based numerical modelling

AbstractThis natural‐scale experimental study combines structural modelling of soft‐linked normal‐fault relays with a CFD (computational fluid dynamics) numerical simulation of a range of unconfined turbidity currents overrunning the relay‐system topography. The flow, released from an upslope inlet gate 2000‐m wide and 50‐m to 100‐m high, rapidly expands and adjusts its thickness, velocity and sediment load to the substrate slope of 1.5°. A lower initial sediment concentration or smaller thickness renders the quasi‐steady flow slower and its sediment‐transport capacity lower. A 3D pattern of large interfering Kelvin‐Helmholtz waves causes fluctuations of the local flow velocity magnitude and sediment concentration. Four zones of preferential sediment deposition are recognized: a near‐gate zone of abrupt flow expansion and self‐regulation; a flow‐transverse zone on the counter‐slope of fault footwall edges; a flow‐transverse zone at the fault‐scarp toes and a similar transverse zone near the crest of the hanging wall counter‐slopes. The sand deposited on the counter‐slope tends to be re‐entrained and fed back to the current by a secondary reverse underflow. The spatial extent and sediment accumulation capacity of depozones depend upon the released current volume. The impact of relay system on an overrunning current depends upon the fault separation distance and stage of tectonic evolution. An early‐stage relay system, with small vertical displacement and little overlap of faults, is bypassed by the current with minimum flow disturbance and no pronounced deposition. An advanced‐stage system, with greater fault displacement and overlap, gives a similar hydraulic effect as a single fault segment if the fault separation is small. If the separation is relatively large, the flow tends to be internally redirected sideways from the ramp into the hanging wall synclinal depressions. Since normal‐fault relays are common features in extensional basins, the study bears important implications for turbiditic slope‐fan models and for the spatial sand prediction in subsurface exploration of faulted submarine slopes.

Study on the Fluid–Structure Interaction at Different Layout of Stacked Chip in Molded Packaging

This study investigates fluid–structure interaction (FSI) analysis of stacked chip in the encapsulation of molded underfill packaging using ANSYS Coupling Work bench with fluid and structural solvers. During encapsulation, FSI analysis is applied to a molded package with different layouts, namely cases 1–4 of stacked chip. An even ratio of inlet and outlet gate pressures is used to produce a regular melt front advancement. An experimental setup is fabricated to validate the simulation results in the FSI study. A digital camera is used to capture the melt front advancement and structural deformation. The interaction between structures (silicon chip) and epoxy molding compound (EMC) is displayed in the displacement profile. Maximum deformation is evaluated during the final stage of filling. The silicon die experiences von Mises stresses, which are monitored to observe the risk of die cracking. The results of this study showed that, the EMC flow front advancement was the fastest in case 4. The pressure distribution of each case was nearly identical, and the maximum von Mises stress was distributed unevenly at the middle of the stacked chip. The proposed analysis can serve as a reference and guide in designing and improving 3D integration packages in industry.

Response of unconfined turbidity current to normal‐fault topography

AbstractTurbidity currents descending the slopes of deep‐water extensional basins or passive continental margins commonly encounter normal‐fault escarpments, but such large‐magnitude phenomena are hydraulically difficult to replicate at small scale in the laboratory. This study uses advanced computational fluid dynamics numerical simulations to monitor the response of large, natural‐scale unconfined turbidity currents (100 m thick and 2000 m wide at the inlet gate) to normal‐fault topography with a maximum relief of nearly 300 m. For comparative purposes, the turbidity current is first released on a non‐faulted pristine slope of 1·5° (simulation model 1). The expanding and waxing flow bypasses the slope without recognizable deposition within the visibility limit of 8 vol.% sand grain packing. Similar flow is then released towards the tip (model 2) and towards the centre (model 3) of a normal‐fault escarpment. In both of these latter models, the sand carried by flow tends to be entrapped in four distinct depozones: an upslope near‐gate zone of flow abrupt expansion and self‐regulation; a flow‐transverse zone at the fault footwall edge; a flow‐transverse zone at the immediate hangingwall; and a similar transverse zone near the crest of the hangingwall counter‐slope, where some of the deposited sand also tends to be reshuffled to the previous zone by a secondary reverse underflow. The near‐bottom reverse flow appears to be generated on a counter‐slope of 1·1°, increased to 2·0° by deposition. The Kelvin–Helmholtz interface instability plays an important role by causing three‐dimensional fluctuations in the flow velocity magnitude and sediment concentration. The thick deposits of large single‐surge flows may thus show hydraulic fluctuations resembling those widely ascribed to hyperpycnal flows. The study indicates further that the turbiditic slope fans formed on such fault topographies are likely to be patchy and hence may differ considerably from the existing slope‐fan conceptual models when it comes to the spatial prediction of main sand depozones.

Topology optimization of composite structures with data-driven resin filling time manufacturing constraint

This paper presents a framework for modeling the data-driven manufacturing constraints and integrating them into the structural topology optimization. The empirical surrogate model of manufacturing constraints is constructed by mining the results of numerical process simulations of massively sampled topologies, using statistical learning. During optimization, the manufacturing constraints are modeled as additional objectives to the structural performance objective, and the multi-objective topology optimization is solved by the Kriging-interpolated level-set (KLS) approach and the multi-objective genetic algorithm (MOGA). The resulting Pareto frontiers offer opportunities to select the designs with some sacrifice in structural performance, yet improved manufacturability. An example of topology optimization of composite structures considering resin filling time showed the process of the proposed framework, and demonstrated its feasibility. Due to the proposed abstract topology features inspired by underlying physics of the filling process, the surrogate model of resin filling time is far more generalizable than the traditional surrogate models based on, e.g., bitmap and local feature representation. In particular, the model can reasonably be applied to the situations with the different inlet gate locations and initial bounding boxes from the training set, while the traditional surrogate models fail in such situations. Three case studies for composite structure topology optimization are discussed with different inlet gate locations and initial bounding boxes in order to show the robustness of the data-driven resin filling time predictive model.

Fast method to monitor the flow front and control injection parameters in resin transfer molding using pressure sensors

The quality of composite parts manufactured by resin transfer molding is sensitive to material and process variations during the preform impregnation. In order to improve the process robustness in two-dimensional injection cases, this work proposes a fast method for tracking and controlling the resin flow through the preform, using only a small number of pressure sensors embedded in the mold. The approach combines pressure signals and flow modeling in a quick algorithm that returns on-line estimations of the flow front profiles. Virtual and real injection tests demonstrated the accuracy of the methodology and provided information for designing the sensing system. Moreover, the investigation proved the feasibility of a simple and effective procedure of flow rate control. Based on a computer-controlled pressure regulator acting on the inlet gate, a feedback mechanism was implemented in the system and allowed keeping the flow front velocity within a target range of values. Such a control procedure may be used to limit the formation of voids and enhance the final part quality.

Fabric compaction and infiltration during vacuum-assisted resin infusion with and without distribution medium

Vacuum infusion experiments with and without distribution medium were carried out in woven E-glass fabric preforms. The experimental set-up was carefully designed to obtain a unidimensional in-plane flow between the inlet and outlet gate, which was combined with through-the-thickness infiltration in the tests carried out with a distribution medium. The variation of the fabric thickness during the infusion experiments was measured by means of digital image correlation, whereas the fluid pressure along the strip was obtained by means of pressure gages. Finally, the in-plane fabric permeability as a function of the fiber volume fraction and the fabric compactability were measured by means of independent tests. The experimental results provided a very detailed picture of the interaction between the fluid infiltration mechanisms and the preform deformation during in-plane and through-the-thickness flow, which is very useful to understand the complex interaction between permeability and compaction during infiltration.

Characterization of textile permeability as a function of fiber volume content with a single unidirectional injection experiment

Textile permeability is a fundamental property to describe preform impregnation in Liquid Composite Molding (LCM) processes. It depends on textile architecture and fiber volume content (FVC). Conventional methods to measure in-plane permeability are based on radial or unidirectional injection experiments performed at fixed FVC. A complete characterization involves a series of tests and requires several material samples. This study presents a novel approach to characterize permeability as a function of FVC through a unique unidirectional injection experiment with a preform containing different FVC sections. The same experimental set-up as in conventional unidirectional unsaturated permeability measurements is used with a second pressure transducer embedded in the mold in addition to the one located at the inlet gate. A fast algorithm is developed to exploit the data from the two sensors and automatically derive the permeability distribution without any need of visual flow front observations. The methodology is validated with a random fiber mat and a woven fabric. Results show that accurate permeability characterization can be achieved for both kinds of textiles.

Reproducibility of LCA models of crude oil production.

Scientific models are ideally reproducible, with results that converge despite varying methods. In practice, divergence between models often remains due to varied assumptions, incompleteness, or simply because of avoidable flaws. We examine LCA greenhouse gas (GHG) emissions models to test the reproducibility of their estimates for well-to-refinery inlet gate (WTR) GHG emissions. We use the Oil Production Greenhouse gas Emissions Estimator (OPGEE), an open source engineering-based life cycle assessment (LCA) model, as the reference model for this analysis. We study seven previous studies based on six models. We examine the reproducibility of prior results by successive experiments that align model assumptions and boundaries. The root-mean-square error (RMSE) between results varies between ∼1 and 8 g CO2 eq/MJ LHV when model inputs are not aligned. After model alignment, RMSE generally decreases only slightly. The proprietary nature of some of the models hinders explanations for divergence between the results. Because verification of the results of LCA GHG emissions is often not possible by direct measurement, we recommend the development of open source models for use in energy policy. Such practice will lead to iterative scientific review, improvement of models, and more reliable understanding of emissions.

Comparison of Different Multi-Strand Tundishes

A computational study was carried out to optimize the positions of outlet strands and to compare the operating parameters of two-strand, four-strand and six-strand tundishes. This involved adoption of an Euler-Lagrangian approach to track spherical particles in a steady, three-dimensional flow field obtained by the numerical solutions of Reynolds-averaged Navier-Stokes and energy equations. The standard k-e model and random walk model were used for modeling the turbulence in flow field and paths of inclusions, respectively. For comparison of different tundishes, two methodologies were adopted, first with equal mass flow rate of liquid steel at the inlet gate for all the tundishes considered (i.e., same capacity) and the second with equal mass flow rate of liquid steel leaving through each outlet strand for all the tundishes. It was found that for different tundishes with the same capacity, a change in the number of outlet strands does not have any significant effect on the operating parameters of the tundishes. For the tundishes with the same flow rate at each strand, the removal efficiency of two strand tundish was found to be more compared to that of four-strand and six-strand tundishes