Compressible Flow Through Solar Power Plant Chimneys

2000 ◽  
Vol 122 (3) ◽  
pp. 138-145 ◽  
Author(s):  
Theodor W. von Backstro¨m ◽  
Anthony J. Gannon
Keyword(s):  
Pressure Drop ◽  
Compressible Flow ◽  
Power Plants ◽  
Step Length ◽  
Wall Friction ◽  
Vertical Acceleration ◽  
Through Flow ◽  
Flow Through ◽  
Thermodynamic Variables ◽  
Additional Losses

Chimneys as tall as 1500 m may be important components of proposed solar chimney power plants. The exit air density will then be appreciably lower than the inlet density. The paper presents a one-dimensional compressible flow approach for the calculation of all the thermodynamic variables as dependent on chimney height, wall friction, additional losses, internal drag and area change. The method gives reasonable answers even over a single 1500 m step length used for illustration, but better accuracy is possible with multiple steps. It is also applicable to the rest of the plant where heat transfer and shaft work may be present. It turns out that the pressure drop associated with the vertical acceleration of the air is about three times the pressure drop associated with wall friction. But flaring the chimney by 14 percent to keep the through-flow Mach number constant virtually eliminates the vertical acceleration pressure drop. [S0199-6231(00)03003-3]

Pressure Drop in Solar Power Plant Chimneys

Solar Energy ◽  
2002 ◽  
Author(s):  
Theodore W. von Backstro¨m ◽  
Andreas Bernhardt ◽  
Anthony J. Gannon
Keyword(s):  
Pressure Drop ◽  
Wall Friction ◽  
Rectangular Section ◽  
Pressure Drops ◽  
Through Flow ◽  
Radial Spokes ◽  
Friction Pressure Drop ◽  
Internal Bracing ◽  
Order Of Magnitude ◽  
Flow Through

The paper investigates the flow through a representative tall solar chimney with seven sets of internal bracing wheels with radial spokes. The paper presents experimental data measured in a 0.63 m diameter laboratory scale chimney model with and without bracing wheels. A fan at one end of the chimney model either sucked or blew the flow through it. The measured friction pressure drop was higher than theoretical values for smooth walls, and swirling, blown flow increased it by another 12%. The seven bracing wheels, each had twelve spokes, each spoke consisting of a pair of rectangular section bars, caused order of magnitude larger pressure drops than wall friction. For the sucked-through flow the forced, swirling, disturbed flow increased the pressure drop by up to 36%. Bracing wheels also increased the exit kinetic energy coefficient to 1.26 with the last wheel at the chimney exit. This effect could in combination with the bracing wheel drag reduce flow through the chimney. Designers of large chimneys should take care to minimise the number of bracing wheels, and possibly to streamline spoke sections. If possible, the top bracing wheel should be far enough from the exit for the flow to reattach to the wall after passing over the spoke attachment rim at the wall.

Characterization of Flow Through Porous Metals

2013 ◽  
Author(s):  
Michael J. Hargather ◽  
Karen A. Thole
Keyword(s):  
Pressure Drop ◽  
Compressible Flow ◽  
Internal Flow ◽  
Porous Metal ◽  
Effective Diameter ◽  
Porous Metals ◽  
Flow Area ◽  
Flow Measurements ◽  
Flow Through

Porous metals have long been considered as an ideal material in which to manufacture turbine components given the inherent large convective surface area. One consideration, however, in using porous metals is the increase in pressure drop that accompanies these materials. To characterize increases in pressure drop for porous materials, flow measurements were made on numerous porous metal coupons. The porosity of the coupons investigated had a range of four in terms of density. A technique for determining the effective internal flow area from pressure drop measurements was developed to provide an effective diameter. The pressure drop measurements were compared to an ideal isentropic compressible-flow nozzle and to a smooth, straight-walled tube. The comparisons show that the porous channels have a similar, but much larger pressure drop than the smooth walls. The experiments performed demonstrated that these porous geometries can be scaled to provide generalized pressure drop characteristics for all geometries.

A Calculation Procedure for Three-Dimensional, Time-Dependent, Inviscid, Compressible Flow through Turbomachine Blades of any Geometry

1979 ◽  
Vol 21 (1) ◽  
pp. 39-49 ◽  
Author(s):  
C. Bosman ◽  
J. Highton
Keyword(s):  
Secondary Flow ◽  
Compressible Flow ◽  
Subsonic Flow ◽  
Three Dimensional ◽  
Experimental Results ◽  
Time Dependent ◽  
Two Dimensional ◽  
Through Flow ◽  
Flow Through ◽  
Inviscid Compressible Flow

A method for calculating three-dimensional, time-dependent, inviscid, subsonic flow is presented. Application is made to flow through the rotor of a small radial inflow turbine and comparison with conventional through-flow calculations and experimental results is made. The nature of the strong secondary flow in this rotor indicates the probable inadequacy of the two-dimensional calculations which is confirmed by the comparison.

scholarly journals EFFECT OF CAVITIES SHAPES ON THE ROUGHNESS FRICTION FACTOR IN PERFORATED AND SLOTTED HORIZONTAL WELLS USED TO DEWATER OPENCAST MINES

2018 ◽  
pp. 9-13
Author(s):  
Duc Huan Tran ◽  
Carsten Drebenstedt
Keyword(s):  
Pressure Drop ◽  
Mining Industry ◽  
Horizontal Wells ◽  
Wall Friction ◽  
Ansys Fluent ◽  
Friction Factors ◽  
Different Types ◽  
Opencast Mines ◽  
Flow Through ◽  
High Reynolds

The horizontal wells have been adapted to use for dewatering purpose in the mining industry. Due to unique characteristics, those horizontal filters are rec-ommended to utilize not only the mechanical strength but also the hydraulic per-formance. Pressure drop along the horizontal well is a major factor that affects the performance of a wellbore. The pressure drop incurs due to four separate effects: wall friction, perforation roughness, inflow acceleration and mixing ef-fects. This work presents the effects of the two first factors in perforated or slot-ted pipes, which correspond to the case of no flow through the wall. Numerical analysis was carried out with different types of perforations and slots. The simu-lated model accomplished using ANSYS Fluent 14.5. The results revealed that at high Reynolds number, the roughness friction factors in circular perforated pipes are significantly greater than those in axial slotted pipes and perpendicular slotted pipes.

Numerical and Experimental Study of Pressure Drop Reduction in a Power Plant Stack

2004 ◽  
Author(s):  
Murthy Lakshmiraju ◽  
Jie Cui ◽  
Stephen Idem ◽  
Sastry Munukutla
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Power Plants ◽  
Experimental Studies ◽  
Maximum Flow ◽  
Scale Model ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through

As governmental regulations on the emission of the power industry became more restrictive, many power plants operating today experience severe problems. The fans that handle the flow through the stack, that were originally designed to handle a certain maximum flow rate, are now required to handle even higher flow rates due to the introduction of emission control devices. In this study, computational fluid dynamics (CFD) and experimental studies have been carried out on the scale model of a stack to identify means for pressure drop reduction. The CFD model was constructed using the commercial software CFX-5.6. The model solves the Reynolds averaged Navier-Stokes equation with Shear-Stress turbulence model (SST) and the CFD results are validated by data taken from the scale model. Baffles of different orientation have been installed in the stack under different flow conditions. Both numerical and experimental results confirm that adding baffles can reduce the pressure drop in a stack significantly. Thus, with minimum effort, power plants can keep running the stacks at a higher flow rate.

Pressure Drop in Solar Power Plant Chimneys

2003 ◽  
Vol 125 (2) ◽  
pp. 165-169 ◽  
Author(s):  
Theodor W. von Backstro¨m ◽  
Andreas Bernhardt ◽  
Anthony J. Gannon
Keyword(s):  
Pressure Drop ◽  
Kinetic Energy ◽  
Separated Flow ◽  
Wall Friction ◽  
Solar Chimney ◽  
Rectangular Section ◽  
Frictional Pressure Drop ◽  
Internal Bracing ◽  
Flow Through ◽  
Kinetic Energy Loss

The paper investigates flow through a representative tall solar chimney with internal bracing wheels. It presents experimental data measured in a 0.63-m-dia model chimney with and without seven bracing wheels. The bracing wheels each had a rim protruding into the chimney and 12 spokes, each spoke consisting of a pair of rectangular section bars. The investigation determined coefficients of wall friction, bracing wheel loss, and exit kinetic energy in a model chimney, for both ideal non-swirling uniform flow and for swirling distorted flow. A fan at one end of the chimney model either sucked or blew the flow through it. The flow entering the chimney through the fan and its diffuser simulated the flow leaving the turbine at the bottom of the chimney. The swirling distorted flow increased the total pressure drop by about 28%, representing 4.7% of the turbine pressure drop. The pressure drop across the bracing wheels exceeded the frictional pressure drop by far. Designers of tall, thin-walled chimneys should take care to minimize the number of bracing wheels, reduce their rim width as much as possible, and investigate the feasibility of streamlining their spoke sections. If at all structurally possible, the top bracing wheel should be far enough from the chimney exit to allow the spoke wakes to decay and the separated flow to re-attach to the chimney wall downstream of the rims before the flow leaves the chimney, to reduce the exit kinetic energy loss.

ESTIMATION OF PRESSURE DROP FOR NON-NEWTONIAN LIQUID FLOW THROUGH BENDS USING ADAPTIVE NON-PARAMETRIC MODEL

2020 ◽  
Vol 47 (1) ◽  
pp. 59-69
Author(s):  
Suman Debnath ◽  
Anirban Banik ◽  
Tarun Kanti Bandyopadhyay ◽  
Mrinmoy Majumder ◽  
Apu Kumar Saha
Keyword(s):  
Pressure Drop ◽  
Liquid Flow ◽  
Parametric Model ◽  
Newtonian Liquid ◽  
Flow Through ◽  
Non Parametric

HEAT TRANSFER AND PRESSURE DROP IN TURBULENT FLOW THROUGH A TUBE WITH LONGITUDINAL PERFORATED STAR-SHAPED INSERTS

2011 ◽  
Vol 18 (6) ◽  
pp. 491-502 ◽  
Author(s):  
Andrew Mintu Sarkar ◽  
M. A. Rashid Sarkar ◽  
Mohammad Abdul Majid
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Turbulent Flow ◽  
Flow Through

Pressure Drop for Oil-Gas Two-Phase Flow Through Straight Horizontal Pipe

2007 ◽  
Author(s):  
Wenhong Liu ◽  
Liejin Guo ◽  
Ximin Zhang ◽  
Kai Lin ◽  
Long Yang ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Flow Through ◽  
Oil Gas
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