Evaluation of air flow resistance across a green fig bed for selecting an appropriate pressure drop prediction equation

The air pressure drop over the nozzles manifolds of inlet fogging system and the flow resistance downstream of the nozzle array (manifold) have always been an area of concern and is the object of this paper. Fogging nozzles arrays (involving several hundred nozzles) are mounted on channels and beams, downstream of the inlet filters and affect the pressure drop. The water injection angle, nozzle injection velocities and the progressive evaporation of the water droplets evaporation all influence the inlet pressure seen at the gas turbine inlet. This paper focuses on a numerical simulation investigation of flow resistance (pressure drop) of inlet fogging systems. In this research effort, the inlet duct is meshed in order to compute the pressure drop over the nozzles frames in fogging and non-fogging conditions. First, the resistance coefficients of an air intake filter are obtained by numerical and experimental methods, and then the coefficients are used for the simulation of the inlet duct by considering the filter as a porous media. Effects of nozzle spread pattern and water injection pattern are then modeled. The results indicate that injection velocity and arrangement of nozzles could have significant effects on the pressure drop and intake distortion, which will affect compressor performance. This paper provides a comprehensive analysis of the pressure drop and evaporation of inlet fogging and will be of value to gas turbine inlet fogging system designers and users.

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Three-Dimensional CFD Model of Pressure Drop in µTAS Devices in a Microchannel

Journal of Electronic Packaging ◽

10.1115/1.4004217 ◽

2011 ◽

Vol 133 (3) ◽

Cited By ~ 2

Author(s):

Damena D. Agonafer ◽

J. Yeom ◽

M. A. Shannon

Keyword(s):

Pressure Drop ◽

Figure Of Merit ◽

Flow Resistance ◽

Three Dimensional ◽

Design Rule ◽

Dynamics Model ◽

Enhance Heat Transfer ◽

Micro Total Analysis Systems ◽

Total Analysis ◽

Adsorption Desorption

Microposts are utilized to enhance heat transfer, adsorption/desorption, and surface chemical reactions. In a previous study [Yeom et al., J. Micromech. Microeng., 19, p. 065025 (2009)], based in part on an experimental study, an analytical expression was developed to predict the pressure drop across a microchannel filled with arrays of posts with the goal of fabricating more efficient micro-total analysis systems (µTAS) devices for a given pumping power. In particular, a key figure of merit for the design of micropost-filled reactors, based on the flow resistance models was reported thus providing engineers with a design rule to develop efficient µTAS devices. The study did not include the effects of the walls bounding the microposts. In this paper, a three-dimensional computational fluid dynamics model is used to include the effects of three-dimensionality brought about by the walls of the µTAS devices that bound the microposted structures. In addition, posts of smaller size that could not be fabricated for the experiments were also included. It is found that the two- and three-dimensional effects depend on values of the aspect ratio and the blockage ratios. The Reynolds number considered in the experiment that ranged from 1 to 10 was extended to 300 to help determine the range of Re for which the FOM model is applicable.

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Research Active Posterior Rhinomanometry Tomography Method for Nasal Breathing Determining Violations

Sensors ◽

10.3390/s21248508 ◽

2021 ◽

Vol 21 (24) ◽

pp. 8508

Author(s):

Oleg G. Avrunin ◽

Yana V. Nosova ◽

Ibrahim Younouss Abdelhamid ◽

Sergii V. Pavlov ◽

Natalia O. Shushliapina ◽

...

Keyword(s):

Computed Tomography ◽

Pressure Drop ◽

Flow Rate ◽

Dynamic Change ◽

Air Flow ◽

Current Mode ◽

Forced Response ◽

Point Of View ◽

Air Flow Rate ◽

Nasal Breathing

This study analyzes the existing methods for studying nasal breathing. The aspects of verifying the results of rhinomanometric diagnostics according to the data of spiral computed tomography are considered, and the methodological features of dynamic posterior active rhinomanometry and the main indicators of respiration are also analyzed. The possibilities of testing respiratory olfactory disorders are considered, the analysis of errors in rhinomanometric measurements is carried out. In the conclusions, practical recommendations are given that have been developed for the design and operation of tools for functional diagnostics of nasal breathing disorders. It is advisable, according to the data of dynamic rhinomanometry, to assess the functioning of the nasal valve by the shape of the air flow rate signals during forced breathing and the structures of the soft palate by the residual nasopharyngeal pressure drop. It is imperative to take into account not only the maximum coefficient of aerodynamic nose drag, but also the values of the pressure drop and air flow rate in the area of transition to the turbulent quadratic flow regime. From the point of view of the physiology of the nasal response, it is necessary to look at the dynamic change to the current mode, given the hour of the forced response, so that it will ensure the maximum possible acidity in the legend. When planning functional rhinosurgical operations, it is necessary to apply the calculation method using computed tomography, which makes it possible to predict the functional result of surgery.

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Heat transfer and pressure drop for air flow through enhanced passages. Final report

10.2172/10155982 ◽

1992 ◽

Cited By ~ 1

Author(s):

N.T. Obot ◽

E.B. Esen

Keyword(s):

Heat Transfer ◽

Pressure Drop ◽

Air Flow ◽

Final Report ◽

Flow Through

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Air Flow Analysis in Square Duct Bend

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.695.622 ◽

2014 ◽

Vol 695 ◽

pp. 622-626 ◽

Cited By ~ 1

Author(s):

Mohamad Nor Musa ◽

Mohd Nurul Hafiz Mukhtar

Keyword(s):

Reynolds Number ◽

Pressure Drop ◽

Cross Section ◽

Air Flow ◽

Flow Analysis ◽

Maximum Velocity ◽

Maximum Pressure ◽

Air Velocity ◽

Square Duct ◽

Inlet Velocity

This paper present new result for experimental analysis of air flow velocity and pressure distributions between two ducts bend: (1) 90° duct bend with a single turning vane having 0.03m radius and (2) 90° duct bend with double turning vane, in 0.06 × 0.06 m duct cross section. The experiment used five different Reynolds numbers chosen between the ranges 1 ×104 and 6×104. Each experiment has four point measurements: (1) point 1 and point 2 at cross section A-A and (2) point 3 and point 4 at cross section B-B. The first experimental study used single turning vane radius 0.03m with inlet air velocity from 2.5m/s to 12.2m/s. And for the second experiment that used square turning vane with 0.03m radius. In experiment 2, the inlet air velocity also start from 2.5m/s to 12.2m/s. From analysis results, the pressure drop in experiment 1 is higher than experiment 2. As example the maximum pressure drop at 7.5m/s inlet air velocity between point 1 and 3 was found to be 71.6203 Pa in experiment 1 as compared to 61.8093 Pa in experiment 2. The velocity after duct bend is greater when using double turning vane compare used single turning vane as maximum velocity at point 3 in experiment 2 compare to velocity at point 3 in experiment 1 that is 55.677× 10-4 m/s and 54.221× 10-4 m/s. The velocity at duct wall is equal to zero. When increase the value of Reynolds number or inlet velocity, the maximum velocity and total pressure also increase. For example in experiment 1 at point 1, the velocity is 48.785 × 10-4 m/s at Reynolds number 1 ×104 and velocity 65.115×10-4 m/s at Reynolds number 12.2 ×104 . Velocity flow in duct section are lower than inlet velocity. In experiment 1, the inlet velocity is 2.5m/s meanwhile the maximum velocity in the duct section at point 2 is 73.075×10-4 m/s that is much more lower than inlet velocity.

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