The Effect of Compressor Exit Flow Distribution on Air Placement in Annular Combustors

1978 ◽  
Vol 100 (3) ◽  
pp. 444-451 ◽  
Author(s):  
R. C. Adkins
Keyword(s):  
Mathematical Model ◽  
Flow Distribution ◽  
Simple Mathematical Model ◽  
Nonuniform Flow ◽  
Flow Conditions ◽  
Design And Development

A simple mathematical model has been devised which is intended to make a powerful aid to combustor design and development. The model has confirmed that nonuniform flow conditions at inlet to the precombustor diffuser can seriously deter combustor performance.

Flowing Polymers Through Porous Media: An Experimental Study of Flow Distribution, Polymer Degradation, and Molecular Weight Effects

1993 ◽  
Vol 46 (11S) ◽  
pp. S63-S70 ◽  
Author(s):  
A. J. Mu¨ller ◽  
L. I. Medina ◽  
O. Pe´rez-Martin ◽  
S. Rodriguez ◽  
C. Romero ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Reynolds Number ◽  
Porous Media ◽  
Flow Resistance ◽  
Polymer Concentration ◽  
Flow Distribution ◽  
Rate Of Change ◽  
Mechanical Degradation ◽  
Nonuniform Flow ◽  
Flow Conditions

The flow of aqueous poly(ethylene oxide) solutions through nonconsolidated porous media has been experimentally investigated. Three aspects of practical relevance have been addressed: the effect of polymer on flow distribution under nonuniform flow conditions, the mechanical degradation of the polymer in the porous media, and the effect of molecular weight on flow resistance. The nonuniform flow results indicate that, although the presence of polymer changes the distribution of the flow by affecting the region of the medium that is swept by the fluid, a significant increase in flow resistance is still observed above a critical Reynolds number, as it happens under uniform flow conditions. The degradation experiments show that the polymer is significantly degraded only in the region where a sizable increase in flow resistance is obtained with respect to the Newtonian behavior. The most significant effect of the molecular weight of the polymer is the fact that an increase in that parameter results in a substantial reduction of the Reynolds number at which the increased flow resistance is observed. Furthermore, the rate of change of this onset Reynolds number with polymer concentration appears to be independent of molecular weight. The results presented here indicate that the increase in flow resistance is not exclusively determined by the shear viscosity of the polymer solution.

scholarly journals Mathematical Model of Airflow in the Lungs of Children I: Effects of Tumor Sizes and Locations

2000 ◽  
Vol 2 (3) ◽  
pp. 199-213 ◽  
Author(s):  
R. A. Segal ◽  
X. Guan ◽  
M. Shearer ◽  
T. B. Martonen
Keyword(s):  
Fluid Dynamics ◽  
Mathematical Model ◽  
Drug Delivery ◽  
Computational Fluid Dynamics ◽  
Flow Distribution ◽  
Bulk Flow ◽  
Physical Factors ◽  
Aerosol Therapy ◽  
Flow Conditions ◽  
Model Lung

To contribute to the development of more effective aerosol therapy protocols in pediatric medicine, we examined airflow patterns in the lung of a four-year-old child. In particular, we addressed how the presence of tumors in airways affected the character of airflow patterns. To study the effects of tumors we employed a computational fluid dynamics package, FIDAP, to define flow conditions within a model lung. The results indicated that tumors have a pronounced affect on both (i) localized velocity profiles in airways and (ii) bulk flow distribution within the lung. By identifying the effects of physical factors on flow conditions the findings will lead to improved drug delivery regimens.

Research on an axial-mounted dual magnetostrictive material rods-based electro-hydrostatic actuator

2021 ◽  
pp. 1045389X2110145
Author(s):  
Yuchuan Zhu ◽  
Chang Liu ◽  
Yunze Song ◽  
Long Chen ◽  
Yulei Jiang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Flow Distribution ◽  
Maximum Flow ◽  
Magnetostrictive Material ◽  
Simulation Techniques ◽  
Motion State ◽  
New Type ◽  
Output Characteristics ◽  
Active Rectification

In this paper, an electro-hydrostatic actuator driven by dual axial-mounted magnetostrictive material rods-based pumps (MMPs) with a new type of active rectification valve is designed in the current study. Based on flow distribution of the active rectification valve and driving energy provided by two MMPs, the actuator can output continuous and bidirectional displacement. By establishing a mathematical model of the actuating system, using simulation techniques, the change rule of hydraulic cylinder’s motion state caused by different driving signals are studied and analyzed. Test equipment platform is constructed in the laboratory to test the output characteristics and confirm the feasibility of the new concept. The experimental results indicate that the maximum flow rate can reach approximately 2.7 L·min−1, while the operating frequency is 180 Hz.

Dune-scale cross-strata across the fluvial-deltaic backwater regime: Preservation potential of an autogenic stratigraphic signature

Geology ◽  
2020 ◽  
Vol 48 (12) ◽  
pp. 1144-1148
Author(s):  
Chenliang Wu ◽  
Jeffrey A. Nittrouer ◽  
Travis Swanson ◽  
Hongbo Ma ◽  
Eric Barefoot ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Mississippi River ◽  
Nonuniform Flow ◽  
Hydrodynamic Conditions ◽  
Flow Conditions ◽  
Bed Topography ◽  
Fundamental Building Block ◽  
Bed Form ◽  
Spatially Varying ◽  
Topography Data

Abstract Dune-scale cross-beds are a fundamental building block of fluvial-deltaic stratigraphy and have been recognized on Earth and other terrestrial planets. The architecture of these stratal elements reflects bed-form dynamics that are dependent on river hydrodynamic conditions, and previous work has documented a multitude of scaling relationships to describe the morphodynamic interactions between dunes and fluid flow. However, these relationships are predicated on normal flow conditions for river systems and thus may be unsuitable for application in fluvial-deltaic settings that are impacted by nonuniform flow. The ways in which dune dimensions vary systematically due to the influence of reach-averaged, nonuniform flow, and how such changes may be encoded in dune cross-strata, have not been investigated. Herein, we explored the influence of backwater flow on dune geometry in a large modern fluvial channel and its implications for interpretation of systematic variability in dune cross-strata in outcrop-scale stratigraphy. This was accomplished by analyzing high-resolution channel-bed topography data for the lowermost 410 km of the Mississippi River, which revealed that dune size increases to a maximum before decreasing toward the river outlet. This spatial variability coincides with enhanced channel-bed aggradation and decreasing dune celerity, which arise due to backwater hydrodynamics. An analytical model of bed-form stratification, identifying spatial variability of cross-set thickness, indicates a prominent downstream decrease over the backwater region. These findings can be used to inform studies of ancient fluvial-deltaic settings, by bolstering assessments of proximity to the marine terminus and associated spatially varying paleohydraulics.

Experimental and Theoretical Analysis of Transient Response of Plate Heat Exchangers in Presence of Nonuniform Flow Distribution

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
N. Srihari ◽  
Sarit K. Das
Keyword(s):  
Steady State ◽  
Heat Exchangers ◽  
Sudden Change ◽  
Temperature Response ◽  
Flow Distribution ◽  
Transient Temperature ◽  
Nonuniform Flow ◽  
Flow Rates ◽  
Plate Heat ◽  
Flow Maldistribution

Transient analysis helps us to predict the behavior of heat exchangers subjected to various operational disturbances due to sudden change in temperature or flow rates of the working fluids. The present experimental analysis deals with the effect of flow distribution on the transient temperature response for U-type and Z-type plate heat exchangers. The experiments have been carried out with uniform and nonuniform flow distributions for various flow rates. The temperature responses are analyzed for various transient characteristics, such as initial delay and time constant. It is also possible to observe the steady state characteristics after the responses reach asymptotic values. The experimental observations indicate that the Z-type flow configuration is more strongly affected by flow maldistribution compared to the U-type in both transient and steady state regimes. The comparison of the experimental results with numerical solution indicates that it is necessary to treat the flow maldistribution separately from axial thermal dispersion during modeling of plate heat exchanger dynamics.

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