scholarly journals Research Active Posterior Rhinomanometry Tomography Method for Nasal Breathing Determining Violations

Sensors ◽  
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.

Plug Flow of Coarse Particles in a Horizontal Pipe

1982 ◽  
Vol 104 (2) ◽  
pp. 198-206 ◽  
Author(s):  
Y. Tsuji ◽  
Y. Morikawa
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Air Flow ◽  
Plug Flow ◽  
Packed Bed ◽  
Coarse Particles ◽  
Air Flow Rate ◽  
Horizontal Pipe ◽  
Main Pipe ◽  
Secondary Air

Plug flow of coarse particles was investigated experimentally in a horizontal pipe, in which a sub-pipe for secondary air injection was installed. Measurements were made about the plug motion, pressure drop, and transportation properties, and the roles of the main and sub-pipe air flow were clarified. The main air flow increases the number of plugs, while the sub-pipe air flow increases the plug velocity. The higher the main pipe air flow rate, the more regular the motion. The height of a stationary layer of deposited particles, which is built on the bottom of the main pipe, decreases with increasing the sub-pipe air flow rate. The pressure drop in the moving plug is quantitatively much smaller than that in the stationary packed bed of same particles.

scholarly journals GUIDELINES FOR THE DESIGN OF AIR BUBBLE SYSTEMS

1976 ◽  
Vol 1 (15) ◽  
pp. 170
Author(s):  
Nabil Ismail
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Air Flow ◽  
Water Systems ◽  
Experimental Results ◽  
Air Flow Rate ◽  
Air Bubble ◽  
Proper Design ◽  
Comprehensive Study ◽  
The Ideal

Based on a literature review of theoretical and experimental work on air-bubble systems, guidelines for the ideal design of submerged distributors discharging air into water are presented. A comprehensive study of gas-liquid dispersions was carried out to find out the effect of physical properties, distributor arrangement, and the air flow rate, on the flow pattern within the jet. This review revealed that the distributor arrangement largely influences the characteristics of the dispersion within the zone of flow establishment. Also, upon analyzing the experimental results of air-water systems, it was found that the zone of flow establishment extends to greater distances of the water depth than that in the case of one-phase turbulent plumes. Furthermore, the experimental results showed that the efficiency of air bubble plumes can be increased by the proper design of the distributor. Recommendations for the distributor design are given, which include, diameter of orifices and their spacings, pressure drop across orifices, number of manifolds, and the maximum air flow rate.

Pressure Drop as a Function of Air Flow Rate for Roll-Punched Transpired Solar Collectors With Different Porosities

2011 ◽  
Author(s):  
Greg Barker ◽  
Kosol Kiatreungwattana
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Air Flow ◽  
Cost Effective ◽  
Solar Collectors ◽  
Air Flow Rate ◽  
Heated Air ◽  
Absorber Material ◽  
Collector Efficiency ◽  
Metal Absorber

Transpired solar collectors are simple and cost-effective devices suited for preheating ventilation air for buildings. They work by drawing outside air through a south-facing perforated metal absorber. The absorber is heated by solar radiation, heat is transferred to the air as it is drawn through the perforations in the absorber, and the pre-heated air is delivered to the building. Often overlooked in the design of transpired collector systems is the effect on collector efficiency of pressure drop across the absorber. The pressure drop is a function of the air flow rate through the perforations, the overall porosity of the absorber, and the properties of the air. The National Renewable Energy Laboratory (NREL) conducted a series of laboratory tests to characterize the pressure drop as a function of the relevant parameters for six commercially-available absorber configurations; three porosities in aluminum and three in steel. Each absorber material is roll-punched to one of three depths to create absorbers with three different porosities. Pressure drop, air flow rate, air temperature, and air relative humidity data were collected during the tests. The data were fit to a model that can be used to predict pressure drop across the absorber as a function of air properties and flow rate. Use of these correlations is expected to aid designers in ensuring that transpired collector systems are designed for optimal thermal efficiency and cost effectiveness.

Numerical Investigation of the Nonreacting Swirling Flow Structure Downstream of Industrial Gas Turbine Burner With the Central Body

2015 ◽  
Author(s):  
Ivan A. Zubrilin ◽  
Dmitriy N. Dmitriev ◽  
Sergey S. Matveev ◽  
Sergey G. Matveev
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Flow Structure ◽  
Flow Rate ◽  
Central Body ◽  
Swirling Flow ◽  
Air Flow ◽  
Air Flow Rate ◽  
Piv Measurements ◽  
Good Agreement

This paper will discuss the investigation of the nonreacting swirling flow downstream of the burner with the central body. This burner is designed for burning partially prepared fuel-air mixture. The burner consists of the axial swirler and the central body. The swirler plays the role of the premixer, and the central body is used to stabilize the flame. The simulation was conducted with the commercial software ANSYS Fluent 15.0. At present, the most widespread CFD approaches to the swirling flow investigation are URANS and LES. In this study URANS is used for obtaining flow charts and LES is used for detailed research of swirling flow structures. The influences of the model parameters (turbulence models, geometry simplification) and numerical parameters (the number of grid elements) on the burner pressure drop are shown in the simulation results. The LES results were compared with the experimental data on the flow structure downstream of the burner. The measurements were provided by 2D PIV with the imaging frequency of 500 Hz and 1000 Hz. It was found that in the investigated range of parameters the burner pressure drop changes slightly and is in good agreement with the experimental data. It was shown that the results of the PIV measurements with the different imaging frequency are in good agreement. The results show that flow behavior achieved in simulation is in accordance with the PIV measurements. It is shown that the flow separation from the central body trailing edge results in formation of large eddies and high velocity fluctuations. On the one hand it can contribute to the mixing of pilot fuel with air, but on the other hand it can lead to high amplitude pressure oscillations during combustion. The form and the frequency of the precessing vortex core were discovered. It was found that the maximum air flow rate through the recirculation zone is about 12% of the total air flow rate through the burner.

scholarly journals Distribution of indoor thoron in dwellings under normal and turbulent flow conditions using CFD simulation technique

2017 ◽  
Vol 32 (2) ◽  
pp. 180-184 ◽  
Author(s):  
Rishi Chauhan ◽  
Amit Kumar ◽  
Neetika Chauhan
Keyword(s):  
Turbulent Flow ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Air Flow ◽  
Point Of View ◽  
Simulation Technique ◽  
Air Flow Rate ◽  
Radon Measurement ◽  
Decay Products ◽  
And Migration

Extensive work has been carried out on measurement of radon and thoron levels in indoor environment in last three decades. These studies are important from radiation protection point of view, if one considered the contribution of radon, thoron and their decay products to total inhalation dose. Numerous studies on radon measurement well established the behaviour of its dispersion in dwellings. But the short lives of thoron cause the difficulty to understand the distribution of thoron in dwellings. The problem becomes more complicated when thoron dispersion is studied under different inlet air flow rate. Different air flow pattern may cause different thoron level at different point in test dwellings causing uncertainty in the measurements. This work utilized the CFD simulation technique for study of indoor thoron dispersion in test dwellings under normal and turbulent flow of air. The simulation study for thoron distribution in a test room was performed for air velocities 0.10 ms-1, 0.25 ms-1, 0.50 ms-1, 1.0 ms-1, 1.5 ms-1, and 2.0 ms-1. The results show that the thoron distribution becomes uniform for the inlet velocity more than 0.5 ms-1 and appropriate to measure indoor thoron concentration. While in normal condition the measured thoron level varies depending upon the location of dosimeter. Thoron diffusion and migration length are also increased with air flow rate.

KARAKTERISTIK HILANG TEKAN ALIRAN UDARA MELALUI TUMPUKAN SERBUK GERGAJI DI FIXED BED REACTOR

EKUILIBIUM ◽  
2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Sunu Herwi Pranolo
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Air Flow ◽  
Fixed Bed ◽  
Average Diameter ◽  
Operating Conditions ◽  
Fixed Bed Reactor ◽  
Air Flow Rate ◽  
Independent Variables ◽  
Bed Porosity

<p>Abstract : Solid Bed in fixed bed gasifier tends to cause the pressure drop that resulting energy<br />loss. Thus, the main cause needs analysis in order to obtain the operating conditions that<br />minimize energy loss. Pressure drop at the fixed bed gasifier is influenced by the particle<br />diameter, bed porosity and shape factor of the solid particle. This research purposed to analyze<br />influence of air flow rate and depth of sawdust bed in the fixed bed gasifier. The experiments<br />were performed by air flux from the blower. This research analyzed two conditions of the<br />gasifier, empty and filled with the bed of sawdust. Average diameter (D<br />p<br />) of 0,02 cm was<br />selected as constant variable and the independent variables were depth of bed (L) and air<br />superficial velocity (G). The experiments air superficial velocities were in the range of 1,3154 –<br />1,3891 g/cm<br />s and depth of bed at 15 cm, 30 cm, 45 cm. Experimental results showed that the<br />trend of the pressure drop is proportional to the air flow rate and to the depth of sawdust bed.<br />2<br />Keywords: pressure drop, sawdust, gasification</p>

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