Inlet Location Research Articles

An increased production capacity by a retrofitted industrial deethanizer column

The industrial ethane recovery column is modified by change in its operating conditions. In this contribution for the modified process, the influences of the reboiler temperature, column operating pressure and feed–inlet location are evaluated on the simulation results. Optimization of the retrofitted plant parameters is performed by using the practical method of response surface methodology (RSM) and the relevant cost estimation procedure. The best design is obtained and it is found that the production capacity is increased up to 18%, in comparison to the base case.

Analysis of the Flow and Temperature Fields of the Cab to Design an Air Supply Inlet Location Using Fluent Simulation Software

Analysis of the Flow and Temperature Fields of the Cab to Design an Air Supply Inlet Location Using Fluent Simulation Software

Flow Characteristics in a Rectangular Mixing Chamber with Two Jets

A ducted rocket is a ramjet propulsion system, and a typical ducted rocket uses two combustion chambers. Metal particles are occasionally added to the fuel in order to increase thrust. For the complete combustion of metal particles in the second combustion chamber, it is important to understand the mixing characteristics in the chamber’s recirculation zone. In this study, the effects of the mixing chamber geometry and velocity ratio on the flow in the chamber were investigated using particle image velocimetry. A total of four mixing chamber geometries and three velocity ratios were considered, and the effects of the size of the metal fuel-simulating particles were also investigated. The experimental results showed that the size of the recirculation zone and the fuel penetration depth were strongly affected by the location of the axial inlet and the size of the particles. As particle size increased, the size of the recirculation zone increased due to the increased momentum of the axial flow. The effects of chamber geometry and velocity ratio on the flow were significant near the mixing region. However, the effects diminished downstream.

Thermosolutal Mixed Convection in an Air Filled Ventilated Enclosure With Slot Wise Embedded Heat and Contaminant Sources

Airflow, heat, and contaminant transfer in a mechanically ventilated two-dimensional rectangular enclosure by discrete heat and contaminant sources as well as external forced convection at various inlet and outlet locations is numerically simulated. Two different enclosure configurations are considered. In configuration A, the cold air is injected at the top of the left vertical wall and exited at the bottom of the right vertical wall. In configuration B, the cold air is injected at the lower edge of the left vertical wall and exited at the top of the right vertical wall. The objective of the study is to find the relative locations of inlet and outlet in order to obtain more effective cooling in the core of the enclosure by maximizing the heat and contaminant removal rate and reducing the overall temperature. The developed mathematical model is governed by the two-dimensional continuity, momentum, energy, and concentration equations. The governing equations in Cartesian co-ordinates are solved by finite volume based semi-implicit method for pressure linked-equations (SIMPLE) algorithm based on a staggered grid system. Results are presented for different values of the Reynolds number, Grashof number, Sherwood number, and Buoyancy ratio in the laminar regime. A convective transport visualization technique is used to study the behavior of physical phenomena due to stream function, thermal, and solutal functions. The results indicate that cooling inside the core of the enclosure is most effective when the inlet is kept at the bottom of the left vertical wall.

Investigation of flow features in an airtight room for various locations of inlet and outlet ports

Investigation of flow features in an airtight room for various locations of inlet and outlet ports

Modeling of concentration polarization and permeate flux variation in a roto-dynamic reverse osmosis filtration system

Concentration polarization (CP) is a critical issue during desalination by cross-flow reverse osmosis (CFRO) filtration system and it is known that shear rate on the membrane surface can help its mitigation. Roto-dynamic filtration systems provide an easy way to generate high shear rate on membrane surface, and hence reducing CP. However the studies related to the growth of CP layer in roto-dynamic CFRO filtration is very limited. In this paper we developed a computational frame-work where flow and solute transport were simulated using ANSYS-Fluent V14.5 but physics of reverse osmosis through the membrane were implemented using “user defined functions” (UDFs). The development of the CP layer in a roto-dynamic CFRO filtration system has been discussed for different operating conditions such as inlet location, rotation speed, gap between the disk and the membrane and feed pressure. The effects of these parameters on permeate flux are also discussed. It is noted that angular speed of rotor and feed pressure are very effective parameters than others to enhance the permeate discharge. The understanding about the CP layer growth and its influence on permeate flux from the present study will help in better and efficient design of roto-dynamic CFRO filtration systems.

Corrosion Failure of Aluminum Heat Exchanger Tubes

This paper investigates the corrosion failure of aluminum tubes on a heat exchanger user to remove heat from the windings of an electric motor. Only the tubes on the perimeter (bottom, top, and sides) at the air inlet location were affected, which is associated with the heat distribution. This investigation concludes that the observed corrosion on the tube is caused by increased chloride concentration from dry out or alternate wetting and drying of the protective aluminum oxide which breaks down, forming a saturated solution of aluminum chloride. The initial aqueous chloride solution is formed by condensation and the high salt content of the inlet air from a marine environment which is then gradually concentrated as it dried out due to heat from the hot nitrogen side of the tube, hence the observed white powder at the tube inlet and vicinity. The concentrated aluminum chloride with an acidic pH of approximately 3.5 becomes very corrosive to the aluminum tubes resulting in the observed pitting and intergranular corrosion. The failure may be seasonal, based on ambient air conditions and the operating temperature of the tube inlet end. Recommendations for prevention are fourfold: change of process/design e.g., dehumidification of the inlet air in order to prevent condensation on the outer tubes; change of material (e.g., use of Incoloy 625 tubes); application of internal coating to prevent condensation (e.g., blast cleaning and coating with a solvent-free epoxy); and replacement of corroded tubes with annual cleaning to remove salts. Selection of the preferred option should involve evaluation of the relative advantages/disadvantages.

Fabrication of PDMS Microfluidic via Room Temperature Rapid Prototyping Process

An in-expensive way of fabricating PDMS microfluidic using room temperature curing process is presented which can be used for both laboratory and commercial scale. The microfluidic was designed using AutoCAD for master mold preparation and subsequently created with SU8 for rapid prototyping process; the micro mixer and the whole mixer were fabricated in less than without using costly fabrication steps. The device profiles were observed for structural integrity and evaluation by dropping two food coloring dyes through the two inlets and collecting the sample at outlet. Flow rate and mixing efficiency were quantitatively measured by analyzing the recorded flow profiles and values of the image collected from the high powered microscope at inlet and outlet locations is fully obtained and will be presented in our next publication

Near surface geophysics: Investigating the dynamic coastal environment — Introduction

The coastal zone is a habitat for much of the world’s population, a key economic driver for fishing, shipping, recreation and tourism, and a critical wetlands ecology. However, the coastal zone is also a dynamic setting undergoing significant change at many different time scales. Large storms, for example, can restructure coastal morphology on the scale of hours or days. Rising sea level or changes in sediment supply will alter the coastline over decades to centuries and longer. These are human-relevant time scales, and such changes can have major impacts on coastal infrastructure, habitability, and ecology. Human activity also impacts the coast; e.g., hardening of coastlines and inlets, reduction in sediment supply due to damming, artificial beach replenishment, extraction of ground water for human consumption and agriculture, and the introduction of pollutants. Both land- and marine-based near-surface geophysical methods can play a significant role in understanding the many processes that impact …

Heat Transfer Effect in an Air Cooled Ventilated Enclosure

Fluid flow and heat transfer in a mechanically ventilated enclosure using a mixed air-distribution system at various levels have been numerically simulated. Thermally activated fluid is supplied through various slots of the vertical channel wall, flush in with the isothermal ceiling and flush out through a port in the opposite wall. The horizontal walls are assumed to be impermeable and adiabatic. Steady, laminar, and incompressible flow under a Boussinesq approximation has been considered, and numerical results for the Navier–Stokes equation and energy equation are obtained using a finite volume method based on the semi-implicit method for pressure linked equations algorithm for the following parameters: locations of inlet and outlets, and different values of Grashof numbers and Reynolds numbers. The proposed numerical model has been validated by comparing its predictions with those of other models’ data in the literature. The validated model is then used to investigate the effects of the Reynolds number and room aspect ratio on the flow velocity and thermal characteristics within the room. The flow structures and thermal activities are studied for Richardson’s number in the range of . Variation of the convection coefficient along the wall for cold and hot fluids at different locations has been investigated, and cooling efficiencies are found to be maximum when the inlet and the outlet are placed at the middle and lower parts, respectively, of the hot and the cold walls.

Estimation of inlet flow rates for image-based aneurysm CFD models: where and how to begin?

Patient-specific flow rates are rarely available for image-based computational fluid dynamics models. Instead, flow rates are often assumed to scale according to the diameters of the arteries of interest. Our goal was to determine how choice of inlet location and scaling law affect such model-based estimation of inflow rates. We focused on 37 internal carotid artery (ICA) aneurysm cases from the Aneurisk cohort. An average ICA flow rate of 245mLmin(-1) was assumed from the literature, and then rescaled for each case according to its inlet diameter squared (assuming a fixed velocity) or cubed (assuming a fixed wall shear stress). Scaling was based on diameters measured at various consistent anatomical locations along the models. Choice of location introduced a modest 17% average uncertainty in model-based flow rate, but within individual cases estimated flow rates could vary by >100mLmin(-1). A square law was found to be more consistent with physiological flow rates than a cube law. Although impact of parent artery truncation on downstream flow patterns is well studied, our study highlights a more insidious and potentially equal impact of truncation site and scaling law on the uncertainty of assumed inlet flow rates and thus, potentially, downstream flow patterns.

Design and fabrication of micro-mixer with short turns angles for self-generated turbulent structures

Micro mixing process is one of the most important drugs, synthesis and process technology. Many expectations toward enhanced fluids miscibility, yield and purity, improved safety, and access to new discovery are directed to the micro mixing technology. In microfluidic technology, mixer is the most important component because of its ability to operate either active or passive micro mixing. The study reports a simple inexpensive and cost effective micro mixer design/simulation/fabrication using 4.3a COMSOL Multi-physics software package and homemade photolithography equipment. The micro mixer was fabricated using PDMS and glass substrate with master mold fabricated with SU8 for rapid prototyping and reusability, the micro mixer and the whole mixer were fabricated in less than 20 min. Mixing profiles were observed for the efficiency evaluation by dropping four samples urine through the four inlets and collecting the sample at outlet. Flow rate and mixing efficiency were quantitatively measured by analyzing the recorded flow profiles and values of the image collected from the high powered microscope at inlet and outlet locations. and sample flow and mixing were compared for flowing efficiency and flow rate using different concentrations and the results indicate that the mixing efficiency of 98% was obtained at Reynolds number (Re) <2.

Investigation of the Inlet and Outlet Location on the Soundproofing Ventilation Unit

This paper deals with A-type and B-type rectangular cuboid SVU (soundproofing ventilation unit) contain an inlet and outlet in opposite surfaces. The difference between them is whether they are located in small or big cross section area. Following the theoretical calculation, the shape and location of the inlet and the outlet are determined by an investigation of the distribution of higher order mode waves formed inside the SVU. Finally, experimental results of A- type and B-type based on the reverberation chamber method are shown to be in reasonable agreement with our theoretical predictions. The results of theoretical calculation and experiments conducted lead to the conclusion that A-type is suitable for soundproof ventilation unit.

Benefits of the controlled reactive high-power impulse magnetron sputtering of stoichiometric ZrO2 films

High-power impulse magnetron sputtering with a pulsed reactive gas (oxygen) flow control was used for high-rate reactive depositions of densified, highly optically transparent, stoichiometric ZrO2 films onto floating substrates. The depositions were performed using a strongly unbalanced magnetron with a directly water-cooled planar Zr target of 100 mm diameter in argon–oxygen gas mixtures at the argon pressure of 2 Pa. The repetition frequency was 500 Hz at the deposition-averaged target power density from 5 Wcm−2 to 53 Wcm−2. The voltage pulse durations ranged from 50 μs to 200 μs. The target-to-substrate distance was 100 mm. An optimized location of the oxygen gas inlets in front of the target and their orientation toward the substrate made it possible to improve the quality of the films due to minimized arcing at the sputtered target and to enhance their deposition rates up to 120 nm/min at the deposition-averaged target power density of 52 Wcm−2, a voltage pulse duration of 200 μs and a substrate temperature less than 120 °C. The films exhibited a hardness of 16 GPa, a refractive index of 2.19 and an extinction coefficient of 2 × 10−3 (both at the wavelength of 550 nm). Under these optimized conditions, we measured the highest (Zr+ + Zr2+) and (O2+ + O+) ion fractions in the total fluxes of positive ions, and a low population of high-energy O− ions at the substrate position.

Analysis of Airflow Pattern in Plant Factory with Different Inlet and Outlet Locations using Computational Fluid Dynamics

【Purpose: This study was conducted to analyze the air flow characteristics in a plant factory with different inlet and outlet locations using computational fluid dynamics (CFD). Methods: In this study, the flow was assumed to be a steady-state, incompressible, and three-dimensional turbulent flow. A realizable k- ${\varepsilon}$ turbulent model was applied to show more reasonable results than the standard model. A CFD software was used to perform the numerical simulation. For validation of the simulation model, a prototype plant factory ( $5,900mm{\times}2,800mm{\times}2,400mm$ ) was constructed with two inlets ( ${\Phi}250mm$ ) and one outlet ( $710mm{\times}290mm$ ), located on the top side wall. For the simulation model, the average air current speed at the inlet was $5.11m{\cdot}s^{-1}$ . Five cases were simulated to predict the airflow pattern in the plant factory with different inlet and outlet locations. Results: The root mean square error of measured and simulated air current speeds was 13%. The error was attributed to the assumptions applied to mathematical modelling and to the magnitude of the air current speed measured at the inlet. However, the measured and predicted airflow distributions of the plant factory exhibited similar patterns. When the inlets were located at the center of the side wall, the average air current speed in the plant factory was increased but the spatial uniformity was lowered. In contrast, if the inlets were located on the ceiling, the average air current speed was lowered but the uniformity was improved. Conclusions: Based on the results of this study, it was concluded that the airflow pattern in the plant factory with multilayer cultivation shelves was greatly affected by the locations of the inlet and the outlet.】

Identification of Inlet and Outlet Locations for Cool Seawater Discharges from an LNG Facility

Two-dimensional hydrodynamic and advection-dispersion simulations were carried out toidentify the appropriate locations of inlet and outlet for cool seawater discharges from the proposed LiquefiedNatural Gas (LNG) terminal using MIKE-21 suites of software. The model simulations were validated bycomparing the observed and simulated hydrodynamics in terms of water depths, current speeds and directions.The model is satisfactorily correlated with coefficients 0.98, 0.86 and 0.91 for water depth, current speed anddirection, respectively. The validated model was extended to predict the advection-dispersion phenomena forthe two scenarios based on positions of inlet and outlet and their discharges. The predicted results of coolwater discharges were compared to the existing Environmental Health and Safety, World Bank guidelines forLNG discharge facilities. It was observed that a trade-off is required before taking engineering decisions forselecting an environmentally acceptable and energy efficient option for such cool water discharges from anLNG facility.

Effects of Inlet Location on Inert Replacement Efficiency of the Gasoline Vapor in Oil Tank

Elimination gasoline vapor in oil tank by mechanical ventilation has disadvantages of long vent time poor safety, and low efficiency, however, those shortcomings can be better conquered if combusted gas is used in the process of the mechanical ventilation. Based on former studies, the research on the effects of inlet location on gasoline vapor’s inert replacement in oil tank by combusted inert gas is studied experimentally in this paper. The conclusions in this paper can provide some useful guidance for the field project of gasoline vapor’s inert replacement in oil tank.

Feasibility and parametric study of tetrahydrofuran dehydration using reactive distillation with low energy requirement

A new configuration of a RD (reactive distillation) process is investigated to break the THF (tetrahydrofuran)/water azeotrope using Hysys process software. The main module is a column system containing the reaction of EO (ethylene oxide) with water, in which top and bottom streams are the desired products, THF and EG (ethylene glycol), respectively. This contribution explores feasibility of using the reaction in the RD column and also describes the influence of reflux ratio, reaction trays, operating pressure and feed–inlet locations of the RD column in simulation environment. The results show that high purities of EG and THF are simultaneously obtained by this novel technique leading to more profits of the RD process. The optimal design of the RD process is obtained by minimizing the energy demand and the optimum number of reactive trays is found to be 10. Furthermore, minimum energy demand is observed when the column operates at atmospheric pressure with reflux ratio of 1.25. Particularly, it is found that the optimal reboiler duty per unit THF produced is reduced from 32 to 3.7% for the new process as compared to the conventional one, while both schemes predict similar outputs.

Liquid water preferential accumulation in channels of PEM fuel cells with multiple serpentine flow fields

This work presents an experimental investigation on the preferential accumulation of liquid water in the channels of a multiple serpentine PEMFC with 50 cm2 active area. Neutron imaging was used for visualizing the liquid water distribution during the cell operation for a wide range of operating conditions. Liquid water accumulation in the cathode channels was observed for most of the operating conditions, with a preferential accumulation in certain channels of the flow field. A statistical analysis was performed in order to determine the main characteristics of this accumulation (i.e. channel number and degree of accumulation). As cathode channels were positioned in vertical direction, it was found that gravity effects had an important influence in the accumulation, as well as the relative position of the channel with respect to the inlet and outlet locations. The gas flow direction had also a major impact on the water accumulation within the channels, with significantly more water accumulated in channels with upwards gas flow.

Application of the CWQII method and a 2D water quality model to assess diversion schemes for East Lake (Donghu), Wuhan, China

The water quality of East Lake, the largest urban lake in China, has continuously deteriorated as a result of urban development. To improve the lake's water quality, a diversion construction project is underway to divert water from the Yangtze River to the lake to accelerate the flow cycle and decrease nutrient concentrations. This study assessed the effects of proposed diversion schemes on water quality using the composite water quality identification index (CWQII) method and a 2-dimensional (2D) water quality model. The study results indicated that the water quality of the lake is strongly influenced by diversion schemes, including diverting locations, discharge, and time. The optimum diversion inlet was inlet 2 (located in Shuiguo Bay), and the most efficient discharge was 30 m3/s. Diverting from different inlet locations caused more obvious reduction rates of CWQII in summer (Jul) than in winter (Jan). After diversion, CWQII values throughout the entire lake were reduced, and the spatial distribution of CWQII became more homogeneous. The highest reduction of CWQII occurred near the inlet location. The CWQII method and 2D water quality model provided a relevant example for assessing the general water quality and designing optimal schemes for diversion projects to improve water quality in large shallow lakes.