Closure to “Discussion of ‘Flow Patterns and Wall Stresses in a Mass-Flow Bunker’” (1973, ASME J. Eng. Ind., 95, p. 26)

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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Flow Patterns and Wall Stresses in a Mass-Flow Bunker

Journal of Engineering for Industry ◽

10.1115/1.3438096 ◽

1973 ◽

Vol 95 (1) ◽

pp. 17-26 ◽

Cited By ~ 38

Author(s):

P. M. Blair-Fish ◽

P. L. Bransby

Keyword(s):

Mass Flow ◽

Small Mass ◽

Flow Patterns ◽

Normal Stresses ◽

Flowing Material ◽

Intense Deformation

Observations are reported of the shear and normal stresses on the walls of a small mass flow bunker and of the variations of density in the flowing material. Changes in wall stresses which occur as the material discharges are correlated with the formation and reformation of zones of intense deformation within the bunker.

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Cooling Air Flow in a Multi Disc Industrial Gas Turbine Rotor

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration ◽

10.1115/98-gt-136 ◽

1998 ◽

Author(s):

D. Brillert ◽

A. W. Reichert ◽

H. Simon

Keyword(s):

Simple Model ◽

Gas Turbine ◽

Boundary Layers ◽

Mass Flow ◽

Radial Flow ◽

Flow Patterns ◽

Navier Stokes ◽

Mean Flow ◽

Flow Through ◽

Secondary Air

The objective of this paper is to investigate the secondary air system in a multidisc rotor. The investigation was performed using Navier-Stokes calculations, network modeling and measurements taking into account new test data from Siemens’ Model V84.3A gas turbine prototype. The objective of the investigation was to better the understanding of flow patterns and to generate a simple model for describing mean flow values. The flow patterns predicted on the basis of Navier-Stokes calculations are described and the losses associated with fluid flow through rotating cavities of multidisc rotors are evaluated. High losses are generated in the radial flow through the corotating discs, and this investigation therefore concentrates on this flow. The investigated mass flowrates are relatively high when compared with the mass flow naturally transported on rotating discs (Cw > 105). One part of the mass flow is forced to flow along the boundary layers. The other part is transported outside of the boundary layers like a free potentially inviscid flow. On the basis of the investigation of the Navier Stokes-calculations, a simple analytical model of the radial flow through the corotating discs is developed. Good agreement was found to exist between the experimental data and the results of the simple model.

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Flow Boiling in a Microtube: Flow Pattern and Heat Transfer

ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels, Volume 2 ◽

10.1115/icnmm2011-58304 ◽

2011 ◽

Author(s):

Giuseppe Zummo

Keyword(s):

Heat Transfer ◽

Flow Pattern ◽

Mass Flow ◽

Slug Flow ◽

Annular Flow ◽

Flow Boiling ◽

Bubbly Flow ◽

Flow Patterns ◽

Flow Instabilities ◽

Internal Diameter

This paper presents the results of the flow boiling patterns of FC-72 in a microtube. The internal diameter of the tube is 0.48 mm, with a heated length of 73 mm. The mass flow rate varies from 50 to 3000 kg/m2-s. The microtube is made of Pyrex in order to obtain the visualisation of the flow pattern along the heated channel. Different types of flow pattern have been observed: bubbly flow, deformed bubbly flow, bubbly/slug flow, slug flow, slug/annular flow, and annular flow. The flow pattern map is compared with those obtained for larger tubes (2.0, 4.0, and 6.0 mm). Flow patterns in the microtube, present less chaotic behaviour and regular vapour-liquid interfaces. Besides, as the tube diameter decreases, the intermittent flow regime shifts from the saturated boiling region towards the subcooled boiling region. The experiments, in the microtube, show the presence of flow instabilities in a large portion of the tests at low mass flow rates and low subcooling. Flow patterns in presence of flow instabilities are mainly characterized by bubbly/slug flow and slug/annular flow. Heat transfer rates have been studied in all flow pattern conditions. The two groups of results, with flow instabilities and without flow instabilities, show similar heat transfer behaviour. The experimental results of flow pattern are compared with the flow pattern maps of McQuillan and Whalley (1985), Mishima and Ishii (1984), and Ong and Thome (2010).

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Numerical Investigations of Flow Features in a Low Pressure Steam Turbine Last Stage Under Different Mass Flow Rates

Volume 8: Microturbines, Turbochargers and Small Turbomachines; Steam Turbines ◽

10.1115/gt2015-42916 ◽

2015 ◽

Cited By ~ 1

Author(s):

Bo Liu ◽

Jiandao Yang ◽

Daiwei Zhou ◽

Xiaocheng Zhu ◽

Zhaohui Du

Keyword(s):

Steam Turbine ◽

Mass Flow ◽

Aerodynamic Force ◽

Flow Patterns ◽

Current Paper ◽

Flow Rates ◽

Flow Features ◽

Mass Flow Rates ◽

Low Mass ◽

Last Stage

In steam turbine plants, the last stages of the low pressure (LP) turbines can deliver up to 20% of the overall power of the plant. It poses lots of challenges to designers especially when the last stages are operated under low volume flow conditions. In the current paper, numerical simulations are conducted to investigate the flow features in a LP steam turbine. In steady calculations, flows under six different mass flow rates are simulated. Performances and flow patterns in last stage rotor (LSR) in low mass flow rates are highlighted. Since the last stage is modeled as a full blade annulus, flow patterns and blade force in circumferential distribution are examined. Results show that under low mass flow rate conditions, vortices occur in the last stage and the diffuser. The LSR acts like a compressor. The periodical distributions of pressure in LSR passages are broken. High amplitude aerodynamic force fluctuations are found on LSR blades in low mass flow cases. By conducting unsteady simulations, the time series of aerodynamic force are demonstrated to have the similar trend and magnitude of that in steady spatial sequence. The mechanism for aerodynamic force excitation is discussed in the current paper. Unsteady pressure fluctuation in tip section of LSR at low mass flow rates seems to have a significant correlation with the aerodynamic force fluctuation level rise.

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