scholarly journals Closure to “Discussion of ‘Aeration Apparatus Converts Bin From Funnel-Flow to Mass-Flow Characteristics’” (1973, ASME J. Eng. Ind., 95, p. 41)

1973 ◽  
Vol 95 (1) ◽  
pp. 41-41
Author(s):  
R. B. Emery
Keyword(s):  
Mass Flow ◽  
Flow Characteristics ◽  
Funnel Flow

Aeration Apparatus Converts Bin From Funnel-Flow to Mass-Flow Characteristics

1973 ◽  
Vol 95 (1) ◽  
pp. 37-41 ◽  
Author(s):  
R. B. Emery
Keyword(s):  
Flow Control ◽  
Mass Flow ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Storage Space ◽  
Flow Problems ◽  
Fine Powders ◽  
Bulk Solid ◽  
Discharge Rates ◽  
Funnel Flow

A properly designed hopper provides cost control through increased unloading reliability, improved storage space utilization, steadier discharge rates, and improved blending of discharged materials. Hoppers have been designed to provide these advantages by providing mass-flow characteristics without application of auxiliary flow promoting devices. Many hoppers are not designed for proper flow. In some cases, limitations on head room, flow rate requirements, or bulk solid characteristics present barriers to design goals of proper flow. Application of aeration can alleviate flow problems in existing hoppers without major changes in hopper configuration and, in addition, it can be helpful in reducing required head room, promoting flow control, and handling some very fine powders. An application of such an aerating device to improve the flow characteristics of fine powders from funnel-flow to mass-flow is discussed in this paper.

scholarly journals Development of Hybrid Airlift-Jet Pump with Its Performance Analysis

2018 ◽  
Vol 8 (9) ◽  
pp. 1413 ◽  
Author(s):  
Dan Yao ◽  
Kwongi Lee ◽  
Minho Ha ◽  
Cheolung Cheong ◽  
Inhiug Lee
Keyword(s):  
Boundary Conditions ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Jet Pump ◽  
Two Phase

A new pump, called the hybrid airlift-jet pump, is developed by reinforcing the advantages and minimizing the demerits of airlift and jet pumps. First, a basic design of the hybrid airlift-jet pump is schematically presented. Subsequently, its performance characteristics are numerically investigated by varying the operating conditions of the airlift and jet parts in the hybrid pump. The compressible unsteady Reynolds-averaged Navier-Stokes equations, combined with the homogeneous mixture model for multiphase flow, are used as the governing equations for the two-phase flow in the hybrid pump. The pressure-based methods combined with the Pressure-Implicit with Splitting of Operators (PISO) algorithm are used as the computational fluid dynamics techniques. The validity of the present numerical methods is confirmed by comparing the predicted mass flow rate with the measured ones. In total, 18 simulation cases that are designed to represent the various operating conditions of the hybrid pump are investigated: eight of these cases belong to the operating conditions of only the jet part with different air and water inlet boundary conditions, and the remaining ten cases belong to the operating conditions of both the airlift and jet parts with different air and water inlet boundary conditions. The mass flow rate and the efficiency are compared for each case. For further investigation into the detailed flow characteristics, the pressure and velocity distributions of the mixture in a primary pipe are compared. Furthermore, a periodic fluctuation of the water flow in the mass flow rate is found and analyzed. Our results show that the performance of the jet or airlift pump can be enhanced by combining the operating principles of two pumps into the hybrid airlift-jet pump, newly proposed in the present study.

scholarly journals Determination of mass flow characteristics of supersonic axisymmetric nozzle diaphragms in modeling variable duties of low-consumption turbines

2020 ◽  
pp. 39-43
Author(s):  
Р.Р. Симашов ◽  
С.В. Чехранов
Keyword(s):  
Mass Flow ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Relative Length ◽  
Axisymmetric Nozzle ◽  
Relative Flow Rate ◽  
Wide Range ◽  
Mass Flow Rates ◽  
Subsonic Part ◽  
Low Consumption

В работе приводятся обобщающие зависимости коэффициентов расхода сопловых аппаратов со сверхзвуковыми осесимметричными соплами в широком диапазоне изменения определяющих геометрических и режимных параметров. Предложена двухпараметрическая функция, учитывающая влияние расположения сопел в сопловом аппарате и степени конфузорности дозвуковой части осесимметричного сопла на коэффициент расхода. Показано слабое влияние на коэффициент расхода относительного радиуса закругления стенки в узкой части сопла и относительной длины дозвуковой части сопла в области их оптимальных значений определенных по минимуму потерь кинетической энергии. Переменные режимы работы сопла учитываются зависимостью относительного коэффициента расхода в функции от числа Рейнольдса в критическом сечении сопла. Полученные в работе эмпирические зависимости позволяют использовать их при моделировании переменных режимов и многорежимной оптимизации малорасходных турбин. The research presents generalizing dependences of mass flow rates in supersonic axisymmetric nozzle diaphragms n a wide range of variation of the governing geometric and operating parameters. A two-parameter function is proposed that takes into account the influence of the location of the nozzles in the nozzle apparatus and the degree of compression of the flow of the subsonic part of the nozzle on the mass flow rate. It is shown that the relative radius of rounding of the nozzle wall in the vicinity of the throat section and the relative length of the subsonic part of the nozzle in the region of their optimal values determined by the minimum of kinetic energy losses have a weak effect on the flow rate. Variable duties of nozzle operation are taken into account by the dependence of the relative flow rate as a function of the Reynolds number in the throat of the nozzle. The empirical dependencies obtained in this work make it possible to use them in modeling variable modes and multi-mode optimization of low-consumption turbines.

scholarly journals Ballast Flow Characteristics of Discharging Pipeline in Shield Slurry System

2019 ◽  
Vol 9 (24) ◽  
pp. 5402
Author(s):  
Yang Wang ◽  
Yimin Xia ◽  
Xuemeng Xiao ◽  
Huiwang Xu ◽  
Peng Chen ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Slurry Flow ◽  
Volumetric Concentration ◽  
Mass Percentage ◽  
Pipe System ◽  
Pipeline Wall ◽  
Slurry Flow Rate

We adopted two-way coupling of discrete and finite elements to examine the non-spherical ballast flow characteristics in a slurry pipe system during a shield project. In the study, we considered the slurry rheological property and the flake shape of the ballast. A ballast size between 17 and 32 mm under different slurry flow rates and ballast volumetric concentration conditions was investigated for determining the law through which the mass flow rate, detained mass percentage, and ballast distribution state are influenced. The results indicate that increasing slurry flow rate and the ballast volumetric concentration increase the mass flow rate; the influence of the latter is stronger. Increases in both in the slurry flow rate and the ballast volumetric concentration can reduce the detained mass percentage in the slurry discharging pipeline, whereas increasing the ballast size has the opposite effect. The increase in both the slurry flow rate and the ballast size changes the ballast motion state. Experiments verified the numerical lifting model of the ballast in the vertical pipeline. The measurements of the actual pipeline wall thickness verified that the simulation results regarding the ballast distribution were accurate.

An Experimental Study of the Flow of R-407C in an Adiabatic Spiral Capillary Tube

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
M. K. Mittal ◽  
R. Kumar ◽  
A. Gupta
Keyword(s):  
Experimental Data ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Capillary Tube ◽  
Flow Characteristics ◽  
Flow Rates ◽  
Tube Test ◽  
Mass Flow Rates ◽  
R 134A

The objective of this study is to investigate the effect of coiling on the flow characteristics of R-407C in an adiabatic spiral capillary tube. The characteristic coiling parameter for a spiral capillary tube is the coil pitch; hence, the effect of the coil pitch on the mass flow rate of R-407C was studied on several capillary tube test sections. It was observed that the coiling of the capillary tube significantly reduced the mass flow rate of R-407C in the adiabatic spiral capillary tube. In order to quantify the effect of coiling, the experiments were also conducted for straight a capillary tube, and it was observed that the coiling of the capillary tube reduced the mass flow rate in the spiral tube in the range of 9–18% as compared with that in the straight capillary tube. A generalized nondimensional correlation for the prediction of the mass flow rates of various refrigerants was developed for the straight capillary tube on the basis of the experimental data of R-407C of the present study, and the data of R-134a, R-22, and R-410A measured by other researchers. Additionally, a refrigerant-specific correlation for the spiral capillary was also proposed on the basis of the experimental data of R-407C of the present study.

What You Need to Know to Reliably Handle Waste Coal

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.

An Experimental Investigation of the Non-Steady Flow Characteristics of a Centrifugal Compressor

1965 ◽  
Vol 180 (1) ◽  
pp. 641-672 ◽  
Author(s):  
R. S. Benson ◽  
A. Whitfield
Keyword(s):  
Experimental Investigation ◽  
Steady Flow ◽  
Mass Flow ◽  
Centrifugal Compressor ◽  
Flow Characteristics ◽  
Flow Conditions ◽  
Rotary Valve ◽  
Low Frequencies ◽  
Pipe System ◽  
Compressor Efficiency

The results are given of an experimental investigation of the flow characteristics of a centrifugal compressor under non-steady flow conditions. The compressor delivered air against a rotary valve with a tee branch located in the pipe system between the compressor and the rotary valve. By varying the areas of a nozzle located at the branch end and orifices in the rotary valve a range of flow conditions could be explored. The tests showed that the surge point was displaced to a point of greater mass flow (thus reducing the flow range of the compressor); the magnitude of the displacement depended on the frequency and amplitude of the pressure pulses. Except for small fluctuations in pressure the overall compressor efficiency was reduced for all the test conditions. The flow characteristic of the compressor, as represented by the pressure-mass flow curves, were displaced under all conditions of pulsating flow, the greatest deviation from steady flow characteristics occurring with largest fluctuations in rotary valve area and at low frequencies.

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