scholarly journals Effects of Flow Baffles on Flow Profile, Pressure Drop and Classification Performance in Classifiers

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1213
Author(s):  
Michael Betz ◽  
Marco Gleiss ◽  
Hermann Nirschl
Keyword(s):  
Pressure Loss ◽  
Collection Efficiency ◽  
Flow Behavior ◽  
Classification Performance ◽  
Operating Conditions ◽  
Flow Profile ◽  
Discrete Phase Model ◽  
Operation Conditions ◽  
Air Classifier ◽  
The Impact

This paper presents a study of the use of flow baffles inside a centrifugal air classifier. An air classifier belongs to the most widely used classification devices in mills in the mineral industry, which is why there is a great interest in optimizing the process flow and pressure loss. Using Computational Fluid Dynamics (CFD), the flow profile in a classifier without and with flow baffles is systematically compared. In the simulations, turbulence effects are modeled with the realizable k–ε model, and the Multiple Reference Frame approach (MRF) is used to represent the rotation of the classifier wheel. The discrete phase model is used to predict the collection efficiency. The effects on the pressure loss and the classification efficiency of the classifier are considered for two operating conditions. In addition, a comparison with experimental data is performed. Firstly, the simulations and experiments show good agreement. Furthermore, the investigations show that the use of flow baffles is suitable for optimizing the flow behavior in the classifier, especially in reducing the pressure loss and therefore energy costs. Moreover, the flow baffles have an impact on the classification performance. The impact depends on the operation conditions, especially the classifier speed. At low classifier speeds, the classifier without flow baffles separates more efficiently; as the speed increases, the classification performance of the classifier with flow baffles improves.

Nacelle Aerodynamic Optimization and Inlet Compatibility

2015 ◽  
Author(s):  
Jingjing Chen ◽  
Yadong Wu ◽  
Zhonglin Wang ◽  
Anjenq Wang
Keyword(s):  
Pressure Loss ◽  
Operating Conditions ◽  
Maximum Pressure ◽  
Aerodynamic Optimization ◽  
Flow Distortion ◽  
Inlet Flow ◽  
Induction System ◽  
Air Intake ◽  
Inlet Flow Distortion ◽  
The Impact

The design of air induction system is targeting to balance the internal and external flow characteristics as well as the structure and aerodynamic integrity. An optimized air intake design that providing velocity and pressure distributions with least drag and maximum pressure recovery could end up at the expense of higher inlet flow distortion and lower stability margin. Indeed, design requirements and considerations at different operating conditions, such as takeoff, and high AOA maneuvers, could be significantly different from that of cruise and level flight. One of the most challenged operating conditions to be certified for FAR33 & FAR25 requirements is ground crosswind condition, when “Engine” is operating statically on the ground with high crosswind presented. It could accommodate inlet separation or distortion resulted from crosswind, and triggers fan or core stall, as well as induces high fan and/or engine vibrations. Studies of engine inlet compatibility become one of the major tasks required during the engine developing phase. This research is a parametric study of using CFD to evaluate operational characteristics of the air induction system. Comparisons of various inlet designs are made and characterized into four categories, i.e., i) Inlet pressure loss, ii) Nacelle drag, iii) Inlet flow distortion, and iv) Inlet Mach distribution. The objective is to assess the impact of air induction design of turbofan upon inlet compatibility. The research introduces the Kriging model and weighting coefficients to optimize internal total pressure loss and external drag using the isolated nacelle model. Bezier equation was used to fit the optimized curves obtained by changing several control points of the baseline configuration of nacelle. To study the impact of asymmetric lip on flow separation in ground crosswind condition, the paper built crosswind model which introduce a inlet boundary as fan face. Comparisons are then made between the original and optimal nacelle, to show correlation between inlet compatibility and air intake profile.

Qualification of Gasket Performance for Vacuum Applications

2010 ◽  
Author(s):  
Walter Lee ◽  
Abdel-Hakim Bouzid ◽  
James Huang
Keyword(s):  
Elevated Temperatures ◽  
Flow Behavior ◽  
Pressure Gauge ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Test Method ◽  
Vacuum System ◽  
Molecular Flow ◽  
Vacuum Level ◽  
The Impact

Gasket performance for vacuum applications has not been well studied. Although a wealth of sealability data has been generated for pressurized systems, little is done with vacuum conditions. A new test method has been developed to study the sealing performance of gaskets for vacuum services. The tests were conducted on a standard ROTT test rig, where a vacuum chamber surrounding the gasket was created by an air pump and monitored by a pressure gauge capable of measuring pressures down to 0.1 Torr. Two levels of vacuum were used: 50 Torr and 3 Torr. Each tested gasket was compressed to various assembly stresses corresponding to the levels defined in the ROTT procedure. After the gasket was compressed to a desired stress and a target vacuum level was reached, the pumping stopped, and the leak rate was measured, using the pressure rise method. The similar leakage results with two very different vacuum levels confirm that sealing a vacuum system is simply to seal ∼1 bar of air. The air leakage was further compared with the helium leak rates obtained from the standard ROTT test with a pressure of 21 bar to determine the correlation between the two data sets. To better understand the effects of pressure and molecular size of a gas, two additional tests at 2 bar, with helium and with nitrogen, were performed. The comparison among all test data suggests that the gases at relatively low pressures follow a molecular flow behavior up to about 55 MPa of gasket stress on the tested material. As a result, a tightness curve that can be used to estimate the vacuum leakage has been established. For applications involving elevated temperatures, thermal behaviors of gaskets determined by other PVRC tests, such as the HOBT and ARLA, can be used to understand the impact of temperature on vacuum performance. A stress-tightness-temperature framework is proposed that can be used to estimate the tightness and leakage of the gasket at high temperatures. Knowing the air leak rates under different operating conditions, a gasket user will be able to determine the suitability of the gasket for a specific vacuum requirement as well as the optimal assembly stress to maintain the desired vacuum level.

Numerical Optimization of a Gravity Dust-Catcher for Improving Operation Efficiency

2017 ◽  
Author(s):  
Yifan Wang ◽  
Armin K. Silaen ◽  
Guangwu Tang ◽  
David Barker ◽  
Chenn Q. Zhou
Keyword(s):  
Blast Furnace ◽  
Gas Flow ◽  
Collection Efficiency ◽  
Total Suspended Solid ◽  
Suspended Solid ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Dust Particles ◽  
Discrete Phase Model ◽  
Dust Catcher

Gravity dust-catchers are widely utilized in steelmaking plants to separate particles from the gas flow produced by the blast furnace (BF). The BF recycle system often experiences high total suspended solid (TSS) levels with a significant increase in sludge generation. This increased sludge generation results in higher costs in operation, chemical treatment and sludge removal. Due to the environmental limitations inside an operating dust-catcher, direct measurement of operating conditions can be extremely difficult. Computational fluid dynamics (CFD) models provide a method of gaining an understanding of the operating conditions and phenomena that occur inside a blast furnace dust-catcher on both full process and detailed levels. In this paper, a numerical geometry of the dust-catcher is designed and simulated under typical operating conditions. The Discrete Phase Model (DPM) is employed to track the flow patterns and paths of dust particles. The collection efficiency performance is evaluated at different conditions (quarter full, half full, and three quarter full). From these results, an alternative design to enhance process efficiency is proposed and investigated.

scholarly journals Reducing the Life Cycle Cost of Swing Check Valves

1996 ◽  
Author(s):  
O. Roorda ◽  
J. D. McNeill ◽  
M. Wright
Keyword(s):  
Life Cycle ◽  
Steady State ◽  
Pressure Loss ◽  
Life Cycle Cost ◽  
Check Valve ◽  
Operating Conditions ◽  
Opening Angle ◽  
Flow Profile ◽  
Seal Design ◽  
Valve Opening

Within the oil and gas industry there is an emerging trend to estimate expenses for pipelines and system components using a Life Cycle Cost (LCC) basis. This paper describes a new sizing model for swing check valves that can assist in significantly reducing the LCC of the valve. The incremental fuel cost of the compressor arising from pressure loss across the valve is the largest component of the valve’s LCC. The valve’s pressure loss can be minimized by correct valve sizing ensuring full valve opening under normal flow conditions. This new sizing program, applied to an NPS 20 natural gas pipeline, can result in cost savings in the order of two times the capital cost of a swing check valve when compared to traditional sizing methods. The pressure loss across the valve is primarily determined by the opening angle of the valve disc during steady state operation. A steady state valve model was developed and formed the basis for a sizing program for swing check valves. The sizing program assists in optimizing the valve for specified operating conditions. Within margins, the valve opening characteristic can be optimized by adjusting the valve sizing parameters such as valve size, disc weight, counter balance mass and position for a specified set of operating conditions. The LCC of a swing check valve can be further reduced by up to 45% through optimization of the valve design. The sizing program was used in a parametric study to assess the areas relevant in the design optimization of the valve. To further reduce the LCC of swing check valves, research should focus on improving the internal flow profile of the valve, reducing disc weight and eliminating the need for counter balance weights through improving low friction seal design.

scholarly journals An Enhanced Electrocoagulation Process for the Removal of Fe and Mn from Municipal Wastewater Using Dielectrophoresis (DEP)

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 485
Author(s):  
Abdulkarim Almukdad ◽  
Alaa H. Hawari ◽  
MhdAmmar Hafiz
Keyword(s):  
Municipal Wastewater ◽  
Operating Conditions ◽  
Electrode Configuration ◽  
Electrode Spacing ◽  
Electrolysis Time ◽  
Applied Current ◽  
Operation Conditions ◽  
Fe And Mn ◽  
Electrocoagulation Process ◽  
The Impact

In this study the removal of Fe and Mn from primary treated municipal wastewater using a new electrode configuration in electrocoagulation was evaluated. The used electrode configuration induced a dielectrophoretic (DEP) force in the electrocoagulation process. The impact of the electrolysis time, electrodes spacing and applied current on the removal of Fe and Mn was evaluated. The maximum removal percentages of Fe and Mn were obtained using an electrolysis time of 60 min, an electrode spacing of 0.5 cm and an applied current of 800 mA. Under these operating conditions and using the new electrodes configuration, the Fe and Mn removals were 96.8% and 66%, respectively. The main advantage of using the DEP-induced electrode configuration was the minimal consumption of the electrodes. The new electrode configuration showed 42% less aluminum content in the reactor compared to the aluminum electrodes with no DEP effect. The energy consumption at the selected operation conditions was 4.88 kWh/m3. The experimental results were comparable with the simulation results achieved by the COMSOL software.

scholarly journals CFD-Based Structural Optimization of Rotor Cage for High-Efficiency Rotor Classifier

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1148
Author(s):  
Xinliang Mou ◽  
Fangchao Jia ◽  
Ying Fang ◽  
Chuanwen Chen
Keyword(s):  
Flow Field ◽  
Structural Optimization ◽  
Field Distribution ◽  
Classification Accuracy ◽  
High Efficiency ◽  
Industrial Applications ◽  
Classification Performance ◽  
Discrete Phase Model ◽  
Rotor Cage ◽  
The Impact

Due to the uneven materials dispersion and high dust concentration in industrial applications of turbo air classifiers, a high-efficiency rotor classifier was designed. Numerical simulations by ANSYS-Fluent 19.0, the effects of rotor cage shape, the number of blades, and the blade profile on the inner flow field, as well as classification performance, were investigated. The simulation results indicated a significant improvement in flow field distribution near the classification surface with the conical rotor cage. Furthermore, there was an average reduction of 10.1% in cut size, as well as a 23.6% increase in classification accuracy. When the number of blades was 36, the flow field distribution between the blades was relatively uniform and a smaller cut size was obtained at a higher classification accuracy. A streamline blade with 52° as the inlet installation angle effectively reduced the impact of the airflow on the blade and eliminated the inertia anti-vortex between blades. The cut size reduction was 4.7–6.3%, with a basically unchanged classification accuracy. The material classification experimental results were in agreement with the simulated results. The discrete phase model (DPM) could well-predict the cut sizes and classification accuracy, but it could not present the fishhook effect. The present study provides theoretical guidance for the structural optimization of an air classifier with a rotor cage.

Research on Sintering Polytechnic of PTFE/Al Reactive Materials

2013 ◽  
Vol 820 ◽  
pp. 25-29
Author(s):  
Jing Bo Wu ◽  
Mao Quan Li ◽  
Shu Hai Zhang ◽  
Yun Long Mei ◽  
Ze Tao Gao
Keyword(s):  
Sintering Temperature ◽  
Operating Conditions ◽  
Process Time ◽  
Sintering Process ◽  
Influence Of Process Parameters ◽  
Reactive Material ◽  
Operation Conditions ◽  
Heat Preservation ◽  
The Impact ◽  
Microstructure Of The Material

PTFE/Al reactive material was prepared via a hot pressed sintering process and comparative experiments were conveyed considering heating rate, sintering temperature and heat preservation time. The internal microstructure of the material was investigated using metallurgical microscope and stereomicroscope. From the investigation the influence of process parameters of hot pressed sintering on the properties of the material were deduced, and the analysis was verified by testing the impact initiation property with drop hammer method. The density of the material was measured according to the Archimedean principle. and the results showed that the best operating conditions of these three factors are 80°C/h, 365°C, and 0.5h, This new method has a higher effectively (short process time) and need lower operation conditions (low sintering temperature and pressure) comparing with the traditional cold sintering process.

scholarly journals Installation of physical simulation of wind load on crane structures

2021 ◽  
Vol 24 (6) ◽  
pp. 1199-1208
Author(s):  
L. A. Sladkova ◽  
V. V. Krylov ◽  
F. A. Kuznetsov
Keyword(s):  
Computer Model ◽  
Physical Simulation ◽  
Flow Simulation ◽  
Dynamic Effect ◽  
Wind Load ◽  
Operating Conditions ◽  
Model Parameters ◽  
Wind Flow ◽  
Operation Conditions ◽  
The Impact

The purpose of the paper is to reproduce a standard wind flow (laminar, turbulent, pulsating modes) to study the impact on crane structures, with the aim to obtain the load values of crane elements most closely approximate to real conditions. When creating an installation, which is related to the field of experimental aerodynamics, the "principle of simulating the main factors determined by the operating conditions of the research object" is adopted to ensure the r eproducibility of test results to the maximum extent. To confirm the performance efficiency of the proposed installation device, its computer model is developed using the CAD software SolidWorks. The computer model parameters are in full geometric agreement with the dimensions of the developed real installation. The use of the installation makes it possible to study the dynamic effect of the wind on the stability of crane structures in various operation modes (change in wind speed, in the mode of load operation, in operation conditions at the wall, etc.). The proposed installation allows to simulate the loads on crane equipment with the possibility of characteristics expanding, for example, its carrying capacity. The generated computer model of the installation makes it possible to reveal the physical picture of wind flow distribution at the installation outlet. The results of wind flow simulation on the proposed installation are confirmed on a computer model with a high degree of convergence of results at wind speeds of 2.5 m/s and lower The installation proposed by the authors will allow to simulate: the value of the real average statistical wind load of various intensity; pulsating component of the wind load; vortex excitation; increase of the available aerodynamic research capability for a real crane structure. The developed installation is a calibration device for external impacts of the wind force on the crane structure.

scholarly journals Schlieren Visualization of Shaping Air during Operation of an Electrostatic Rotary Bell Sprayer: Impact of Shaping Air on Droplet Atomization and Transport

Coatings ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 279 ◽  
Author(s):  
Adnan Darwish Ahmad ◽  
Ahmad Abubaker ◽  
Ahmad Salaimeh ◽  
Nelson Akafuah
Keyword(s):  
Automotive Industry ◽  
Flow Behavior ◽  
Paint Film ◽  
Target Surface ◽  
Operating Conditions ◽  
Centrifugal Forces ◽  
Droplet Transport ◽  
The Impact ◽  
Insight Into

Electrostatic rotary bell sprayers (ERBSs) are widely used in the automotive industry. In ERBS, atomization is facilitated using centrifugal forces which disintegrate the paint film inside the cup into droplets at the cup edge. The droplets are then transported by the flow of a shaping air (SA) and electrostatic forces to a target surface; the characteristics of these droplets dramatically influence the quality of a painted surface and the painting transfer efficiency. In the current paper, a novel Schlieren-based visualization of the shaping air in the absence of paint droplets was performed during a qualitative investigation to delineate shaping air flow behavior and its interaction with droplets and droplet transport. An infrared thermographic flow visualization (IRFV) method and droplet size measurement were used to complement the Schlieren data for providing insight into shaping air-droplet interactions. The results demonstrated the impact of different operating conditions on the SA flow pattern, and the influence SA has on the secondary atomization and transport of droplets. Hence, these experimental methods combine with a useful tool for optimizing SA configurations that improve spray quality, droplet transport, and the efficiency of ERBS operations.

Investigation on the control of multiphase flow behavior in a continuous casting tundish during ladle change

2020 ◽  
Vol 117 (6) ◽  
pp. 619
Author(s):  
Rui Xu ◽  
Haitao Ling ◽  
Haijun Wang ◽  
Lizhong Chang ◽  
Shengtao Qiu
Keyword(s):  
Multiphase Flow ◽  
Flow Behavior ◽  
Rolled Strip ◽  
Impact Zone ◽  
Steel Cleanliness ◽  
Carry Over ◽  
Slag Carry Over ◽  
Hot Rolled ◽  
Turbulence Inhibitor ◽  
The Impact

The transient multiphase flow behavior in a single-strand tundish during ladle change was studied using physical modeling. The water and silicon oil were employed to simulate the liquid steel and slag. The effect of the turbulence inhibitor on the slag entrainment and the steel exposure during ladle change were evaluated and discussed. The effect of the slag carry-over on the water-oil-air flow was also analyzed. For the original tundish, the top oil phase in the impact zone was continuously dragged into the tundish bath and opened during ladle change, forming an emulsification phenomenon. By decreasing the liquid velocities in the upper part of the impact zone, the turbulence inhibitor decreased considerably the amount of entrained slag and the steel exposure during ladle change, thereby eliminating the emulsification phenomenon. Furthermore, the use of the TI-2 effectively lowered the effect of the slag carry-over on the steel cleanliness by controlling the movement of slag droplets. The results from industrial trials indicated that the application of the TI-2 reduced considerably the number of linear inclusions caused by ladle change in hot-rolled strip coils.

Sign in / Sign up

Export Citation Format

Share Document