scholarly journals Boundary Layer Control by Means of Strong Injection

1984 ◽  
Vol 51 (1) ◽  
pp. 27-34 ◽  
Author(s):  
R.-J. Yang ◽  
M. Holt
Keyword(s):  
Pipe Flow ◽  
Pipe Wall ◽  
Flow System ◽  
Wall Jet ◽  
Direction Parallel ◽  
Coal Gas ◽  
Coal Gasifier ◽  
Gas Products ◽  
Strong Injection ◽  
Layer Control

The gas mixture produced by coal gasifier contains components that have serious corrosive effects on the walls of the pipe flow system. To reduce these, a non-corrosive gas is injected into the stream of the coal gas products, in a direction parallel to the pipe wall. The interaction between the injected stream and the original pipe flow is investigated analytically and is an example of the so-called Wall Jet Problem.

scholarly journals Perspective on the Response of Turbulent Pipe Flows to Strong Perturbations

Fluids ◽  
2021 ◽  
Vol 6 (6) ◽  
pp. 208
Author(s):  
Liuyang Ding ◽  
Tyler Van Buren ◽  
Ian E. Gunady ◽  
Alexander J. Smits
Keyword(s):  
Pipe Flow ◽  
Abrupt Change ◽  
Pipe Wall ◽  
Surface Condition ◽  
Initial Response ◽  
Body Of Revolution ◽  
Future Directions ◽  
Pipe Flows ◽  
Roughness Elements ◽  
Pipe Geometry

Pipe flow responds to strong perturbations in ways that are fundamentally different from the response exhibited by boundary layers undergoing a similar perturbation, primarily because of the confinement offered by the pipe wall, and the need to satisfy continuity. We review such differences by examining previous literature, with a particular focus on the response of pipe flow to three different kinds of disturbances: the abrupt change in surface condition from rough to smooth, the obstruction due to presence of a single square bar roughness elements of different sizes, and the flow downstream of a streamlined body-of-revolution placed on the centerline of the pipe. In each case, the initial response is strongly influenced by the pipe geometry, but far downstream all three flows display a common feature, which is the very slow, second-order recovery that can be explained using a model based on the Reynolds stress equations. Some future directions for research are also given.

Effects of Organic Additives on Calcium Sulfate Scaling in Pipes

2009 ◽  
Vol 62 (8) ◽  
pp. 927 ◽  
Author(s):  
Tung A. Hoang ◽  
H. Ming Ang ◽  
Andrew L. Rohl
Keyword(s):  
Pipe Flow ◽  
Calcium Sulfate ◽  
Chemical Structure ◽  
Flow System ◽  
Organic Additives ◽  
Pipe System ◽  
Calcium Sulfate Scale ◽  
First Time ◽  
Over Time ◽  
Comprehensive Study

A comprehensive study of the effects of nine organic additives on the formation of calcium sulfate scale in a pipe system was conducted using a multiple pipe flow system. Several factors that influence the inhibitory capability of phosphonic and carboxylic additives such as their chemical structure, their concentration, and the run time were closely scrutinized. Results showed that the organic additives influence the deposition of calcium sulfate on the walls of a pipe flow system at various levels. The superiority of the phosphonic additives, especially N,N,N′,N′-ethylenediaminetetramethylenephosphonic acid (EDTP) and nitrilotrimethylenephosphonic acid (NTMP), to other organic compounds with respect to scale prevention is discussed thoroughly. For the first time, it was demonstrated that a solution with a given concentration of inhibitor that is continuously refreshed in a pipe reactor becomes less effective over time. The morphology of the scales formed in the presence of different additives is also studied, using scanning electron microscopy.

scholarly journals Experimental Evaluation of Simplified IGCC

1984 ◽  
Author(s):  
M. W. Horner ◽  
J. C. Corman
Keyword(s):  
Gas Turbine ◽  
Pilot Scale ◽  
Combined Cycle ◽  
Experimental Program ◽  
Inlet Temperature ◽  
Fuel System ◽  
Fuel Gas ◽  
Capital Costs ◽  
Coal Gas ◽  
Coal Gasifier

Integrated gasification combined cycle (IGCC) power plants offer the opportunity to burn coal in an environmentally sound manner at a competitive cost of output energy. Advanced simplified IGCC systems have been identified which offer reduced fuel system capital costs and complexity as well as improved thermal efficiency of coal to fuel conversion. These systems, however, must utilize hot gas cleanup devices to remove particulates, alkali metals, and sulfur to permit utilization of the product fuel gas in a gas turbine. Technology and component development are underway to prepare the hot fuel gas cleanup and gas turbine systems for subsequent integration and verification testing at pilot scale. An experimental testing program is underway to address fuel system and gas turbine components technology for a simplified IGCC configuration. Gas turbine nozzle sectors have been adapted for installation in a turbine simulator for development testing. A low-Btu gas combustor installed upstream of the nozzle sectors is utilized to burn a hot coal gas. Modifications have been made to an existing pilot scale coal gasifier to deliver 1000°F low-Btu coal gas to the gas turbine combustor after partial cleanup by a hot cyclone to remove particulate matter carried over from the coal gasifier. The results from this experimental program will resolve technical issues related to corrosion, deposition and erosion phenomena related to fuel quality, turbine inlet temperature, and nozzle metal surface temperature.

scholarly journals NOx Results From Two Combustors Tested on Medium BTU Coal Gas

1982 ◽  
Author(s):  
T. P. Sherlock ◽  
D. E. Carl ◽  
G. Vermes ◽  
J. Schwab ◽  
J. J. Notardonato
Keyword(s):  
Liquid Fuel ◽  
Coal Gas ◽  
Coal Gasifier ◽  
Product Gas ◽  
Gas Heating ◽  
Percent Conversion ◽  
The Rich ◽  
Inlet Conditions ◽  
Combustion Tests ◽  
Conversion Efficiencies

This paper describes the results of combustion tests of two scaled burners using actual coal gas from a 25 ton/day fluidized bed coal gasifier. The two combustor configurations studied were a ceramic-lined, staged rich/lean burner and an integral, all metal multi-annular swirl burner (MASB). The tests were conducted over a range of temperatures and pressures representative of current industrial combustion turbine inlet conditions. Tests on the rich lean burner were conducted at three levels of product gas heating values: 104, 197 and 254 Btu/Scf. Corresponding levels of NOx emissions were 5, 20 and 70 ppmv. Nitrogen was added to the fuel in the form of ammonia, and conversion efficiencies of fuel nitrogen to NOx were found to be on the order of 4 to 12 percent, which is somewhat lower than the 14 to 18 percent conversion efficiency when SRC-II liquid fuel was used. The MASB was tested only on medium Btu gas (220 to 270 Btu/Scf), and produced approximately 80 ppmv NOx at rated engine conditions. It is concluded that both burners operated similarly on actual coal gas and ERBS fuel, and that all heating values tested can be successfully burned in current machines.

Analysis of Equivalent Pipe Flow System for K-10-8G Combustor

Volume 4 ◽  
2004 ◽  
Author(s):  
Sivasankar Ganesan ◽  
Vijay Subramanian
Keyword(s):  
Flow Visualization ◽  
Pipe Flow ◽  
Pressure Loss ◽  
Flow System ◽  
Initial Flow ◽  
The Core ◽  
Branching Points ◽  
Hardy Cross ◽  
Flow Circuit ◽  
Good Agreement

The pressure loss in the K-10-8G combustor has been quantified by constructing an equivalent pipe flow circuit where, the obstructions and branching are analogous to the flow pattern in the combustor. The adoption of skin friction coefficients and Hardy-Cross method cannot be employed due to the combustor’s short length (550 mm). For the evaluation of pressure loss, three flow systems have been constructed. In the first two systems, the fluid volume flowing through the core divides equally at the corresponding branching points, mixes with the flow from the outer annulus and combines back again. The third system is similar to the first except that the volumes combining after mixing are equal. The initial flow distributions in the core, outer and inner annuli were obtained from flow visualization. These systems can be used for corroborating the pressure loss produced, around 4.12%, which is in good agreement to that found from flow visualization (4.14%). The equivalent system was found to be similar to the combustor.

scholarly journals Impact of Main Pipe Flow Velocity on Leakage and Intrusion Flow: An Experimental Study

Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 118 ◽  
Author(s):  
Yu Shao ◽  
Tian Yao ◽  
Jinzhe Gong ◽  
Jinjie Liu ◽  
Tuqiao Zhang ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Pipe Flow ◽  
Pressure Difference ◽  
Discharge Coefficient ◽  
Pipe Wall ◽  
Technical Note ◽  
Opposite Pattern ◽  
Main Pipe ◽  
Pressurized Pipelines ◽  
The Impact

The classic orifice equation is commonly used to calculate the leakage and intrusion rate for pressurized pipelines with cracks on the pipe wall. The conventional orifice equation does not consider the effect of the flow velocity in the main pipe, and there is a lack of studies on this matter. For this technical note, the influence of the main pipe flow velocity on the outflow and inflow through a crack on the pipe wall was studied in the laboratory. The experimental results show that the impact of the main pipe flow velocity can be significant. When the pressure difference across the orifice was constant, with the increase of the main pipe flow velocity, the outflow velocity increased, but the contraction area of the jet and the outflow discharge coefficient decreased. By comparing orifices with different shapes, it was found that the discharge from the circumferential crack was most sensitive to the main pipe flow velocity. In addition, the main pipe flow promoted the orifice inflow. When the pressure difference across the orifice was constant, with the increase of the main pipe flow velocity, the inflow discharge coefficient increased, which is the opposite pattern to that of the orifice outflow.

Receptivity of pipe Poiseuille flow

1996 ◽  
Vol 315 ◽  
pp. 119-137 ◽  
Author(s):  
Anatoli Tumin
Keyword(s):  
Collocation Method ◽  
Poiseuille Flow ◽  
Chebyshev Polynomials ◽  
Pipe Flow ◽  
Pipe Wall ◽  
Numerical Procedure ◽  
Amplitude Distribution ◽  
Narrow Gap ◽  
Method Of Solution ◽  
Similar Character

The receptivity problem is considered for pipe flow with periodic blow–suction through a narrow gap in the pipe wall. Axisymmetric and non-axisymmetric modes (1, 2, and 3) are analysed. The method of solution is based on global eigenvalue analysis for spatially growing disturbances in circular pipe Poiseuille flow. The numerical procedure is formulated in terms of the collocation method with the Chebyshev polynomials application. The receptivity problem is solved with an expansion of the solution in a biorthogonal eigenfunction system, and it was found that there is an excitation of many eigenmodes, which should be taken into account. The result explains the non-similar character of the amplitude distribution in the downstream direction that was observed in experiments.

The Effect of Blade Manipulator in Fully Developed Pipe Flow

1992 ◽  
Vol 114 (4) ◽  
pp. 687-689 ◽  
Author(s):  
Y. A. Mah ◽  
B. C. Khoo ◽  
Y. T. Chew
Keyword(s):  
Boundary Layer ◽  
Pipe Flow ◽  
Pipe Wall ◽  
Stress Measurement ◽  
Volumetric Flow Rate ◽  
Rate Measurement ◽  
Flow Rate Measurement ◽  
Equivalent Boundary ◽  
Layer Flow ◽  
Wall Shear Stress Measurement

Experiments were carried out in applying the concept of passive device called BLADEs (boundary-layer alteration devices) to fully developed pipe flow to assess its feasibility as a drag reduction device. The results of both the volumetric flow rate measurement and the pipe wall pressure distribution taken far downstream show that there is a net increase in drag with the device. With BLADES in tandem arrangement, there is a further net increase in drag which is contrary to its counterpart in boundary layer flow. Although the wall shear stress measurement following the device indicates some reduction in local drag, its magnitude of reduction is much smaller than that seen in the equivalent boundary flow. All these results suggest little possibility of any useful application of BLADEs to pipe flow.

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