Bunker Design—Part 1: Bunker Outlet Design and Initial Measurements of Wall Pressures

Experiments have shown that the Jenike bunker outlet design method is accurate with respect to both the flow pattern (mass flow or funnel flow) and the minimum outlet required. Initial measurements of wall pressures in a 0.6-m-dia mass flow bunker were used to select a suitable measuring technique for use in larger scale equipment, which is also described.

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Discussion: “Aeration Apparatus Converts Bin From Funnel-Flow to Mass-Flow Characteristics” (Emery, R. B., 1973, ASME J. Eng. Ind., 95, pp. 37–41)

Journal of Engineering for Industry ◽

10.1115/1.3438152 ◽

1973 ◽

Vol 95 (1) ◽

pp. 41-41

Author(s):

A. W. Jenike

Keyword(s):

Mass Flow ◽

Flow Characteristics ◽

Funnel Flow

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What You Need to Know to Reliably Handle Waste Coal

17th International Conference on Fluidized Bed Combustion ◽

10.1115/fbc2003-155 ◽

2003 ◽

Author(s):

Roderick J. Hossfeld ◽

David A. Craig ◽

Roger A. Barnum

Keyword(s):

Mass Flow ◽

Systematic Approach ◽

Flow Patterns ◽

Handling System ◽

Flow Problems ◽

Energy Facility ◽

Anthracite Culm ◽

Funnel Flow ◽

Major Consideration ◽

Waste Coal

Many power producers have been designing for, or switching to waste coal. A major consideration when dealing with waste coal is the design of the fuel handling system. Since waste coal is typically finer and more cohesive and therefore harder to handle in silos, bunkers, chutes and feeders, design of the handling system for reliable, non-stagnant flow is essential. This paper describes a systematic approach to designing and retrofitting handling systems to avoid bulk solids flow problems. Potential trouble areas such as coal hoppers, silos, bunkers, and transfer chutes are discussed. Mass flow and funnel flow patterns that develop in silos and bunkers are presented. Funnel flow results in large stagnant regions, which are a major problem for coals that combust easily and are prone to problems such as arching and ratholing. Mass flow patterns, which eliminate the stagnant coal regions, are also explained. Coal properties and bunker designs that result in mass flow and funnel flow are described. Transfer chute design techniques to avoid pluggages, reduce dusting, and minimize chute wear are discussed. The Panther Creek Energy facility in Nesquehoning, Pennsylvania is used as an example where solids flow handling methodologies were used to solve handling problems with anthracite culm. The modifications presented were required for reliable, stagnant-free coal flow, which prevented belt slippage and high belt loading on gravimetric feeders.

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Identification of Wake Convection and Flow Outline in the Interface Region of Blade Rows With Axial Gap in a Counter Rotating Turbine

Volume 1: Compressors, Fans, and Pumps; Turbines; Heat Transfer; Structures and Dynamics ◽

10.1115/gtindia2019-2634 ◽

2019 ◽

Author(s):

Rayapati Subbarao ◽

M. Govardhan

Keyword(s):

Flow Pattern ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Three Dimensional ◽

Interface Region ◽

Turbine Stage ◽

Deviation Angle ◽

Flow Rates ◽

Improved Performance

Abstract In a Counter Rotating Turbine (CRT), the stationary nozzle is trailed by two rotors that rotate in the opposite direction to each other. Flow in a CRT stage is multifaceted and more three dimensional, especially, in the gap between nozzle and rotor 1 as well as rotor 1 and rotor 2. By varying this gap between the blade rows, the flow and wake pattern can be changed favorably and may lead to improved performance. Present work analyzes the aspect of change in flow field through the interface, especially the wake pattern and deviation in flow with change in spacing. The components of turbine stage are modeled for different gaps between the components using ANSYS® ICEM CFD 14.0. Normalized flow rates ranging from 0.091 to 0.137 are used. The 15, 30, 50 and 70% of the average axial chords are taken as axial gaps in the present analysis. CFX 14.0 is used for simulation. At nozzle inlet, stagnation pressure boundary condition is used. At the turbine stage or rotor 2 outlet, mass flow rate is specified. Pressure distribution contours at the outlets of the blade rows describe the flow pattern clearly in the interface region. Wake strength at nozzle outlet is more for the lowest gap. At rotor 1 outlet, it is less for x/a = 0.3 and increases with gap. Incidence angles at the inlets of rotors are less for the smaller gaps. Deviation angle at the outlet of rotor 1 is also considered, as rotor 1-rotor 2 interaction is more significant in CRT. Deviation angle at rotor 1 outlet is minimum for this gap. Also, for the intermediate mass flow rate of 0.108, x/a = 0.3 is giving more stage performance. This suggests that at certain axial gap, there is better wake convection and flow outline, when compared to other gap cases. Further, it is identified that for the axial gap of x/a = 0.3 and the mean mass flow rate of 0.108, the performance of CRT is maximum. It is clear that the flow pattern at the interface is changing the incidence and deviation with change in axial gap and flow rate. This study is useful for the gas turbine community to identify the flow rates and gaps at which any CRT stage would perform better.

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Fluid Flow and Heat Transfer Characteristics of Slug Bubbly Flow in Micro Condensers

First International Conference on Integration and Commercialization of Micro and Nanosystems, Parts A and B ◽

10.1115/mnc2007-21102 ◽

2007 ◽

Author(s):

J. S. Hu ◽

Christopher Y. H. Chao

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Heat Transfer Coefficient ◽

Pressure Drop ◽

Transfer Coefficient ◽

Flow Pattern ◽

Mass Flow ◽

Flow Rate ◽

Bubbly Flow ◽

Mixed Flow

Experiments were carried out to study the condensation flow pattern in silicon micro condenser using water as medium. Five flow patterns were identified under our experimental conditions. Slug-bubbly flow and droplet/liquid slug flow were found to be the two dominant flows in the micro condenser. These two flow patterns subsequently determined the heat transfer and pressure drop properties of the fluid. It was observed that only slug-bubbly flow existed in low steam mass flow and high heat flux conditions. When the steam mass flow rate increased or the heat flux dropped, mixed flow pattern occurred. An empirical correlation was obtained to predict when the transition of the flow pattern from slug-bubbly flow to mixed flow could appear. In the slug-bubbly flow regime, heat transfer coefficient and pressure drop in the micro condensers were studied. It was found that micro condensers with smaller channels could exhibit higher heat transfer coefficient and pressure drop. At constant heat flux, increasing the steam mass flow rate resulted in a higher heat transfer coefficient and also the pressure drop.

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Modeling on the Effect of Imbalance Burner Pressure and Mass Flow Rate in a Full-Scale Gas Fired Industrial Boiler

Volume 1: Fora, Parts A, B, C, and D ◽

10.1115/fedsm2003-45437 ◽

2003 ◽

Author(s):

Hasril Hasini ◽

Mohd. Zamri Yusoff ◽

Kamsani Abdul Majid ◽

Mohd. Rizal Ramli ◽

Hamdan Hassan ◽

...

Keyword(s):

Temperature Distribution ◽

Flow Pattern ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Cfd Simulation ◽

Combustion Process ◽

General Purpose ◽

Anticlockwise Direction ◽

Industrial Boiler

CFD simulation of the combustion process in a 120MW gas fired industrial boiler has been performed, with focus on the flow pattern and temperature distribution at the reheater section in the furnace. The modeling was done using general-purpose CFD software, CFD-ACE+ developed by CFD Research Corporation. The effect of imbalance burner pressure is simulated by varying the mass flow rate of fuel (natural gas) injected at each burner. The simulation result shows good qualitative agreement with practical observation. The flow in the furnace is highly swirling with intense mixing and follows a helical pattern in an anticlockwise direction. Temperature distribution prior to entry to the reheater is significantly higher on the right side of the reheater. As a conclusion, the imbalance nozzles pressure creates uneven mass flow rate of air and fuel, which results in asymmetric flow pattern and temperature distribution at the reheater section.

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Innovative design to enhance solids discharge from conical bottom ion-exchange columns. Part 1

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1243/095440805x33153 ◽

2005 ◽

Vol 219 (4) ◽

pp. 367-374 ◽

Cited By ~ 1

Author(s):

M Daas ◽

A. V. Retnaswamy ◽

R Srivastava

Keyword(s):

Particle Size ◽

Flow Pattern ◽

Discharge Rate ◽

Innovative Design ◽

Flow Problems ◽

Bulk Solids ◽

Wide Range ◽

Problems And Solutions ◽

Funnel Flow ◽

Conical Bottom

An investigation of flow problems and solutions, associated with bulk solids discharging from conical-bottom cylindrical storage containers, is presented in this paper. The feasibility and efficiency of bulk solids discharging from these containers are directly associated with the flow pattern of the solids. The influence of a new vessel design on the flow pattern and the discharge rate of solids was examined. Glass beads of fixed particle size distribution and density were used to conduct the study. Retrofitting techniques that are commonly used to improve the flow pattern characteristics in silos were reviewed. Two techniques, utilization of inserts and hopper in hopper were investigated, and the results from the first technique are discussed. This technique is based on the usage of a double pyramid-shaped insert to manipulate the flow pattern of discharging solids. Both dry and wet tests were conducted under a wide range of low to moderate pressures. The results from both dry and wet tests showed that the pyramid insert was able to significantly change the flow pattern from the undesired funnel flow to the most desired mass flow and also increase the rate of discharge.

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Translocation of 11C from leaves of Helianthus, Heracleum, Nymphoides, Ipomoea, Tropaeolum, Zea, Fraxinus, Ulmus, Picea, and Pinus: comparative shapes and some fine structure profiles

Canadian Journal of Botany ◽

10.1139/b79-106 ◽

1979 ◽

Vol 57 (8) ◽

pp. 845-863 ◽

Cited By ~ 34

Author(s):

R. G. Thompson ◽

D. S. Fensom ◽

R. R. Anderson ◽

R. Drouin ◽

W. Leiper

Keyword(s):

Fine Structure ◽

Flow Pattern ◽

High Activity ◽

Plant Species ◽

Mass Flow ◽

Reverse Flow ◽

Tracer Activity ◽

Period 2 ◽

Nonsteady State ◽

Sucrose Loading

A 3-min pulse of 11CO2 was fed to leaves of various plant species to allow us to compare the patterns of movement of 11C translocate over 90 min. Three groups of profiles were found. (1) In Helianthus, Nymphoides, Tropaeolum, Ipomoea, and Fraxinus, a mass flow passed successive detectors, rising steadily over a 90-min period. (2) In Zea and Triticum, the mass flow remained at a peak for 5–10 min and fell steadily thereafter. (3) In Picea and Pinus, no obvious mass-flow pattern was detected in 90 min but rather a series of waves or packets. In every case, the activity opposite certain positions accumulated faster than others, suggesting that points of local buildup of translocate occur along a stem or petiole.By using high activity 11CO2 counting times of 5 s or 1 s, and the five-point mean technique of analysis of data, we have been able to detect aberrations in the tracer profile opposite each detector. These aberrations are due in part to the movement of tracer at different speeds in parallel veins, in part to the superposition of reverse flow of tracer, and in part to apparent discontinuities of flow or small waves of tracer. We conclude that some pulsatory sucrose loading mechanism is possible in the leaves, but a nonsteady-state translocatory mechanism is also possible. We have developed techniques for detecting the points of time of the onset of mass flow and the method of following small peaks of tracer activity past successive detectors. Waves of translocate moved at 0.2 cm min−1 in pine and spruce and 0.5–10 cm min−1 in ash and the angiosperms. Some synchrony of flow causes activity reinforcement or interference to occur in transient fashion.

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Particle abrasion of lifting elbow in dilute pneumatic conveying

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650120951293 ◽

2020 ◽

pp. 135065012095129

Author(s):

Yun Ji ◽

Songyong Liu ◽

Dianrong Gao ◽

Jianhua Zhao

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Design Method ◽

Orthogonal Design ◽

Industrial Applications ◽

Experimental Results ◽

Solid Mass ◽

Airflow Velocity ◽

Two Phase

Elbows are widely used in various industrial fields and are important for industrial applications. In this study, Eulerian coupling method was used to address the fluid-particle, and particle-particle interactions in a gas-solid two-phase flow while considering the effects of lifting angle, airflow velocity, and solid mass flow rate. The Hertz-Mindlin contact model and empirical Erosion/Corrosion Research Center erosion model were used to predict erosion in a lifting elbow, and the erosion ratio was used for validation with the experimental results. Experimental results indicated that the established model herein is accurate with different airflow velocities and lifting angles. The orthogonal design method was applied to the simulation scheme design, and range and variance analyses were used for the analysis of the results. Results indicated that the solid mass flow rate most affected elbow erosion comparing with lifting angles and airflow velocities. Additionally, the effect of the elbow lifting angle on the erosion mechanism was considered, and results indicated that the maximum erosion region is independent of the airflow velocity, lifting angle, and solid mass flow rate.

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