Pressure Drop of Unidirectional Air Flow Through Rock Beds

1981 ◽  
Vol 24 (4) ◽  
pp. 1010-1013 ◽  
Author(s):  
Pitam Chandra ◽  
Louis D. Albright ◽  
Gerald E. Wilson
Keyword(s):  
Pressure Drop ◽  
Air Flow ◽  
Flow Through

scholarly journals Air Distributor Designs for Fluidized Bed Combustors: A Review

2016 ◽  
Vol 6 (3) ◽  
pp. 1029-1034 ◽  
Author(s):  
A. Shukrie ◽  
S. Anuar ◽  
A. N. Oumer
Keyword(s):  
Pressure Drop ◽  
Fluidized Bed ◽  
Air Flow ◽  
Fluidized Bed Combustion ◽  
Key Factors ◽  
Successful Operation ◽  
Factors Affecting ◽  
Plate Design ◽  
Flow Through ◽  
Critical Overview

Fluidized bed combustion (FBC) has been recognized as one of the suitable technologies for converting a wide variety of biomass fuels into energy. One of the key factors affecting the successful operation of fluidized bed combustion is its distributor plate design. Therefore, the main purpose of this article is to provide a critical overview of the published studies that are relevant to the characteristics of different fluidized bed air distributor designs. The review of available works display that the type of distributor design significantly affects the operation of the fluidized bed i.e., performance characteristics, fluidization quality, air flow dynamics, solid pattern and mixing caused by the direction of air flow through the distributors. Overall it is observed that high pressure drop across the distributor is one of the major draw backs of the current distributor designs. However, fluidization was stable in a fluidized bed operated at a low perforation ratio distributor due to the pressure drop across the distributor, adequate to provide uniform gas distribution. The swirling motion produced by the inclined injection of gas promotes lateral dispersion and significantly improves fluidization quality. Lastly, the research gaps are highlighted for future improvement consideration on the development of efficient distributor designs.

Heat Exchange Effectiveness and Pressure Drop for Air Flow Through Perforated Plates With and Without Crosswind

1994 ◽  
Vol 116 (2) ◽  
pp. 391-399 ◽  
Author(s):  
C. F. Kutscher
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Pressure Drop ◽  
Air Flow ◽  
Ambient Air ◽  
Perforated Plates ◽  
Wind Speeds ◽  
New Type ◽  
Flow Through ◽  
Heat Exchange Effectiveness

Low-porosity perforated plates are being used as absorbers for heating ambient air in a new type of unglazed solar collector. This paper investigates the convective heat transfer effectiveness for low-speed air flow through thin, isothermal perforated plates with and without a crosswind on the upstream face. The objective of this work is to provide information that will allow designers to optimize hole size and spacing. In order to obtain performance data, a wind tunnel and small lamp array were designed and built. Experimental data were taken for a range of plate porosities from 0.1 to 5 percent, hole Reynolds numbers from 100 to 2000, and wind speeds from 0 to 4 m/s. Correlations were developed for heat exchange effectiveness and also for pressure drop. Infrared thermography was used to visualize the heat transfer taking place at the surface.

Enhanced CFD Modelling and LDA Measurements for the Air-Flow in an Aero-Engine Front Bearing Chamber: Part II

2014 ◽  
Author(s):  
J. Aidarinis ◽  
A. Goulas
Keyword(s):  
Pressure Drop ◽  
Rotational Speed ◽  
Ball Bearing ◽  
Complex Geometry ◽  
Computational Study ◽  
Air Flow ◽  
Mathematical Form ◽  
Operational Parameters ◽  
Aero Engine ◽  
Flow Through

A detailed computational study of the air-flow through the outer gap of the front bearing of an aero-engine is presented. The reason to carry out this study was to understand the flow through the bearing as a function of the operational parameters of the engine, which was necessary for the modeling of the flow in the whole bearing chamber. The complex geometry and the size of the bearing gap relative to the overall dimensions of the bearing chamber and the need for very precise and detailed information of the effect on the flow within the chamber of the bearing operational parameters, prohibited the solution of the flow through the gap together with the rest of the bearing chamber. A 3-D modeling of the flow through the outer bearing gap, which included a section of the ball bearing, was performed. Functions relating the pressure drop of the air coming through the bearing gap and the tangential component of velocity of the air exiting the bearing region, to the mass of air through the gap of the ball bearing and the rotational speed of the shaft were developed. The effect of the lubrication oil within the bearing was modeled as an anisotropic porous medium with a predefined law. In order to acquire in a mathematical form the above relationships a series of computational runs were performed. These relationships, in the form of second order curves, were subsequently introduced to the model of the bearing chamber as described in [1]. The constants of the relationships were derived through comparisons of the calculations with the experimental data. From the analysis it was concluded that the pressure drop across the bearing increases with the square of the rotational speed of the shaft with the mass flow of air through the ball bearing as a parameter and vice versa. For this particular ball bearing there is a region where, for any combination of rotational speed of the shaft and pressure drop through the bearing, there is no flow of air through the bearing. In this paper the detailed modeling methodology, the computational flow field, the boundary conditions and finally the results are presented and discussed.

Enhanced Computational Fluid Dynamics Modeling and Laser Doppler Anemometer Measurements for the Air-Flow in an Aero-engine Front Bearing Chamber—Part II

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
J. Aidarinis ◽  
A. Goulas
Keyword(s):  
Pressure Drop ◽  
Rotational Speed ◽  
Ball Bearing ◽  
Computational Study ◽  
Air Flow ◽  
Cfd Modeling ◽  
Mathematical Form ◽  
Operational Parameters ◽  
Aero Engine ◽  
Flow Through

A detailed computational study of the air-flow through the outer gap of the front bearing of an aero-engine is presented. The reason to carry out this study was to understand the flow through the bearing as a function of the operational parameters of the engine, which was necessary for the modeling of the flow in the whole bearing chamber. The complex geometry and the size of the bearing gap relative to the overall dimensions of the bearing chamber and the need for very precise and detailed information of the effect on the flow within the chamber of the bearing operational parameters, prohibited the solution of the flow through the gap together with the rest of the bearing chamber. A 3D modeling of the flow through the outer bearing gap, which included a section of the ball bearing, was performed. Functions relating the pressure drop of the air coming through the bearing gap and the tangential component of velocity of the air exiting the bearing region, to the mass of air through the gap of the ball bearing and the rotational speed of the shaft were developed. The effect of the lubrication oil within the bearing was modeled as an anisotropic porous medium with a predefined law. In order to acquire in a mathematical form the above relationships a series of computational runs were performed. These relationships, in the form of second order curves, were subsequently introduced to the model of the bearing chamber as described by Aidarinis and Goulas (2014, “Enhanced CFD Modeling and LDA Measurements for the Air-Flow in an Aero Engine Front Bearing Chamber (Part I),” ASME Paper No. GT2014-26060). The constants of the relationships were derived through comparisons of the calculations with the experimental data. From the analysis, it was concluded that the pressure drop across the bearing increases with the square of the rotational speed of the shaft with the mass flow of air through the ball bearing as a parameter and vice versa. For this particular ball bearing, there is a region where, for any combination of rotational speed of the shaft and pressure drop through the bearing, there is no flow of air through the bearing. In this paper the detailed modeling methodology, the computational flow field, the boundary conditions and finally the results are presented and discussed.

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