NEW CALCULATING METHOD OF NASAL RESISTANCE APPLICABLE TO ANY PREDETERMINED POINTS ON DIFFERENTIAL PRESSURE/FLOW CURVE

The running state of the fan has significant influence on the safety and economy of the power plant unit, so it is necessary to monitor the fan performance and running state in real time. According to the basic theory of the fan, there is a stable, good nonlinear mapping relation between the inlet pressure difference and flow, which can be utilized to monitor the flow of the fan. Thus, the fan differential pressure - flow curve model is established by the optimized BP neural network and the modified Support Vector Machine (SVM). The fitting error shows that the improved SVM model is better. Finally, the on-line fan monitoring system software is established by using Visual Basic (VB) language and Matlab programming based on the improved SVM fan differential pressure - flow curve model, which can accurately monitor the fan operation.

Download Full-text

Nasal resistance and flow resistive work of nasal breathing during exercise: effects of a nasal dilator strip

Journal of Applied Physiology ◽

10.1152/jappl.2000.89.3.1114 ◽

2000 ◽

Vol 89 (3) ◽

pp. 1114-1122 ◽

Cited By ~ 21

Author(s):

J. M. Gehring ◽

S. R. Garlick ◽

J. R. Wheatley ◽

T. C. Amis

Keyword(s):

Flow Curve ◽

Cycle Ergometer ◽

Work Rate ◽

Nasal Resistance ◽

Flow Limitation ◽

Nasal Airflow ◽

Nasal Breathing ◽

External Work ◽

Pressure Flow ◽

Nasal Vestibule

Using posterior rhinomanometry, we measured nasal airflow resistance (Rn) and flow-resistive work of nasal breathing (WONB), with an external nasal dilator strip (ENDS) and without (control), in 15 healthy adults (6 men, 9 women) during exclusive nasal breathing and graded (50–230 W) exercise on a cycle ergometer. ENDS decreased resting inspiratory and/or expiratory Rn (at 0.4 l/s) by >0.5 cmH2O · l−1· s in 11 subjects (“responders”). Inspired ventilation (V˙i) increased with external work rate, but tended to be greater with ENDS. Inspiratory and expiratory Rn (at 0.4 l/s) decreased asV˙i increased but, in responders, tended to remain lower with ENDS. Inspiratory (but not expiratory) Rn at peak nasal airflow (V˙n) increased as V˙i increased but, again, was lower with ENDS. At a V˙i of ∼35 l/min, ENDS decreased flow limitation and hysteresis of the inspiratory transnasal pressure-flow curve. In responders, ENDS reduced inspiratory WONB per breath and inspiratory nasal power values during exercise. We conclude that ENDS stiffens the lateral nasal vestibule walls and, in responders, may reduce the energy required for nasal ventilation during exercise.

Download Full-text

Normal Nasal Resistance

Otolaryngology ◽

10.1177/019459988509300616 ◽

1985 ◽

Vol 93 (6) ◽

pp. 778-785 ◽

Cited By ~ 35

Author(s):

John F. Pallanch ◽

Thomas V. McCaffrey ◽

Eugene B. Kern

Keyword(s):

Flow Curve ◽

Nasal Resistance ◽

Pressure Flow ◽

Log Transformation ◽

Nasal Symptoms ◽

Before And After ◽

The Mean ◽

The Right ◽

Normal Adults

Eighty normal adults without nasal symptoms were studied to determine normal nasal resistance values and the variation of nasal resistance in normal adults. A microprocessor-based system for collection and analysis of transnasal pressure and flow was used to obtain nasal resistance values. Unilateral and total transnasal pressure and flow values were determined before and after decongestion of the nose with 1% phenylephrine spray. The distribution of the 80 resistance values was found to be skewed to the right. Log transformation of the resistance values was the best method to normalize their distribution. The mean and variation of normal nasal resistance are reported at flows of 0.1 and 0.2 L/sec, at pressures of 0.5 and 1 cm H2O, and at radii of 1, 2, and 3 on the pressure-flow curve.

Download Full-text

Hydraulic fluid power. Valves. Determination of differential pressure/flow rate characteristics

10.3403/30163926u ◽

2019 ◽

Keyword(s):

Flow Rate ◽

Differential Pressure ◽

Fluid Power ◽

Hydraulic Fluid ◽

Pressure Flow

Download Full-text

Pressure-flow curve derived from coronary CT angiography for detection of significant hemodynamic stenosis

European Radiology ◽

10.1007/s00330-020-06821-w ◽

2020 ◽

Vol 30 (8) ◽

pp. 4347-4355

Author(s):

Xinzhou Xie ◽

Didi Wen ◽

Ruichen Zhang ◽

Qian Tao ◽

Ce Wang ◽

...

Keyword(s):

Ct Angiography ◽

Flow Curve ◽

Coronary Ct Angiography ◽

Pressure Flow ◽

Coronary Ct

Download Full-text

Development of Design Support System for Piping Route and Differential Pressure Flowmeter by Three-Dimensional Fluid Analysis

Volume 1: Beyond Design Basis; Codes and Standards; Computational Fluid Dynamics (CFD); Decontamination and Decommissioning; Nuclear Fuel and Engineering; Nuclear Plant Engineering ◽

10.1115/icone2020-16745 ◽

2020 ◽

Author(s):

Takatsugu Miura ◽

Kingo Igarashi ◽

Tomoyuki Hosaka ◽

Takumi Kitagawa ◽

Tatsurou Yashiki ◽

...

Keyword(s):

Conventional Method ◽

Flow Rate ◽

Flow Measurement ◽

Lower Cost ◽

Differential Pressure ◽

Pipe Axis ◽

Pressure Flow ◽

Fluid Analysis ◽

Analysis System ◽

Analysis Models

Abstract In power plants that becoming more compact, it will expend much time and effort to satisfy the requirement for the differential pressure flow measurement according to ISO’s standards. Therefore, it is difficult for engineers in the design phase to completely remove the potential for large errors in flow measurement. This paper presents the 3D fluid analysis system that is a lower cost than the conventional method to confirm the soundness of such measurement in the phase of piping route design. This system has the function to automatically generate the analysis models from general 3D piping CAD data. The analysis program is written by the open source code to reduce a license fee. Also, this system has the function of calculating the swirl strength along the pipe axis as one of the means for efficiently supporting the design change. In order to verify and validate the analysis system, we analyzed several flow paths, confirmed the response of the swirl strength and flow rate indication value of the differential pressure flowmeter model. The analysis result well simulated the increase or decrease swirl strength in the complex flow path, and fluctuation of the flow rate indication value. Also, the system supports to set the flowmeter in the appropriate position by providing visualization of the swirl strength along the pipe axis. In the flow path analysis in this validation, it took about one month to visualization of the swirl strength along the pipe axis from the generation of the analysis models. The 3D fluid analysis system collaborative with 3D piping CAD design system has been developed. This system enable to confirm the effects of swirl strength on flow measurement and the soundness of the differential pressure flow measurement at a lower cost in comparison with conventional method.

Download Full-text

Increased Nasal Resistance Induced by the Pressure-Flow Technique and its Effect on Pressure and Airflow during Speech

The Cleft Palate-Craniofacial Journal ◽

10.1597/1545-1569_1991_028_0261_inribt_2.3.co_2 ◽

1991 ◽

Vol 28 (3) ◽

pp. 261-266 ◽

Cited By ~ 1

Author(s):

Hui Liu ◽

Donald W. Warren ◽

Rodger M. Dalston

Keyword(s):

Nasal Resistance ◽

Pressure Flow

Download Full-text

A Theory of Blood Flow in Skeletal Muscle

Journal of Biomechanical Engineering ◽

10.1115/1.3108401 ◽

1988 ◽

Vol 110 (1) ◽

pp. 20-26 ◽

Cited By ~ 15

Author(s):

G. W. Schmid-Scho¨nbein

Keyword(s):

Skeletal Muscle ◽

Blood Flow ◽

Flow Curve ◽

Oscillatory Flow ◽

Viscoelastic Model ◽

Low Flow ◽

Pressure Flow ◽

Closed Form Solutions ◽

Wide Range ◽

Theoretical Results

A theoretical analysis of blood flow in the microcirculation of skeletal muscle is provided. The flow in the microvessels of this organ is quasi steady and has a very low Reynolds number. The blood is non-Newtonian and the blood vessels are distensible with viscoelastic properties. A formulation of the problem is provided using a viscoelastic model for the vessel wall which was recently derived from measurements in the rat spinotrapezius muscle (Skalak and Schmid-Scho¨nbein, 1986b). Closed form solutions are derived for several physiologically important cases, such as perfusion at steady state, transient and oscillatory flows. The results show that resting skeletal muscle has, over a wide range of perfusion pressures an almost linear pressure-flow curve. At low flow it exhibits nonlinearities. Vessel distensibility and the non-Newtonian properties of blood both have a strong influence on the shape of the pressure-flow curve. During oscillatory flow the muscle exhibits hysteresis. The theoretical results are in qualitative agreement with experimental observations.

Download Full-text

Experimental Investigation of Static Pressure Characteristics of FBG Differential Pressure Flow Sensor

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.336-338.134 ◽

2013 ◽

Vol 336-338 ◽

pp. 134-138 ◽

Cited By ~ 1

Author(s):

Chun Tong Liu ◽

Zhen Xin He ◽

Yang Zhang ◽

Hong Cai Li

Keyword(s):

Static Pressure ◽

Sensitivity Coefficient ◽

Differential Pressure ◽

Flow Sensor ◽

Experimental Result ◽

Hydraulic Pressure ◽

Hysteresis Phenomenon ◽

Pressure Flow ◽

Pressure Calibrator ◽

Pressure Characteristics

On the basis of FBG (Fiber Bragg Grating) sensor principle analysis, a differential pressure flow sensor using FBG has been designed. The static pressure characteristics of the sensor were experimental studied by the hydraulic pressure calibrator and Q8384 spectrometer, and the experimental result errors were analyzed. Experimental results show that, the sensitivity coefficient of FBG is 3 pm/KPa in the differential pressure range of 0~0.35 MPa. The changes of Bragg wavelength with the pressure changes showing a good linear relationship and repetitive, and the hysteresis phenomenon is minor, which can be used for flow measurement of hydraulic system in special areas.

Download Full-text