192 Verification of Scale Effect on Pressure Drop Characteristics in Curved Rectangular Ducts with Change of Cross Sectional Area

2016 ◽  
Vol 2016.51 (0) ◽  
pp. 181-182
Author(s):  
Kota KOBAYASHI ◽  
Yosuke HATA ◽  
Takashi FUKUE ◽  
Koichi HIROSE ◽  
Fumiaki KUSAKABE ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Scale Effect ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional

Influence of the Cross Sectional Area of a Separation Column Using Structured Packing

2003 ◽  
Author(s):  
Rosa H. Cha´vez ◽  
Javier de J. Guadarrama ◽  
Osbaldo Pe´rez ◽  
Abel Herna´ndez-Guerrero
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Separation Efficiency ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Structured Packing ◽  
Separation Column ◽  
Transfer Unit ◽  
The Cross

In order to determine the dimension of a separation column, hydrodynamic and mass transfer models are necessary to evaluate the pressure drop and the height of the global mass transfer unit, respectively. Those parameters are a function of the cross sectional area of the column. The present work evaluates the dependency of the pressure drop and height of the global transfer unit with respect to the cross sectional area of the column, using an absorption column with high efficiency structured packing, in order to recover SO2 in the form of NaHSO3, as an example. An optimization was done applying Two Film model which is based on the number of global mass transfer units of both gas and liquid, involving the separation efficiency in terms of the height of a global transfer unit. Structured packing, geometrically heaped in a separation column, has been achieving wider acceptance in the separation processes due to their geometric characteristics that allow them to have greater efficiency in the separation processes. Three different structured packing were evaluated in this work. The results show how ININ packing is one of the packings does the best work having the highest separation efficiency because it has the lowest height of the global mass transfer unit and Mellapak packing has the largest capacity because it manages the largest liquid and gas flows. An analysis is done with respect to the pressure drop through the system for all packings considered, and a discussion is presented for each hydrodynamic and mass transfer parameter studied.

Viscous flow in collapsible tubes of slowly varying elliptical cross-section

1977 ◽  
Vol 81 (2) ◽  
pp. 273-294 ◽  
Author(s):  
Rosemary Wild ◽  
T. J. Pedley ◽  
D. S. Riley
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Transverse Velocity ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Collapsible Tube ◽  
Experimental Conditions ◽  
Cross Sectional ◽  
Elliptical Cross ◽  
Collapsible Tubes

This paper is concerned with steady flow in collapsible tubes, such as veins, at fairly low Reynolds number. Lubrication theory is used to calculate the velocity and pressure distribution in an elliptical tube whose cross-sectional area and eccentricity vary slowly and in a given way with longitudinal distance x. The transverse velocity field and the effect of inertia on the primary velocity and pressure distributions are calculated to first order in the relevant small parameter. The results of these calculations are combined with a relationship between transmural pressure and the cross-sectional area at any x which is close to that measured in (large) veins, and are used to predict the pressure and flow in a collapsible tube when a given distribution of external pressure is applied. Different relationships between the tube perimeter and cross-sectional area are examined. The theory is applied to an experiment in which a segment of collapsible tube is supported between two rigid segments, and squeezed; predictions of the relationship between the pressure drop and flow rate are made for various experimental conditions. In particular, when the resistance of the downstream rigid segment is held constant, a range of flow rates is found in which the pressure drop falls as the flow rate is raised; this agrees with experiment.

Air and Power Requirements for the Pneumatic Transport of Crushed Coal in Vertical Pipelines

1975 ◽  
Vol 97 (1) ◽  
pp. 101-106 ◽  
Author(s):  
J. L. Konchesky ◽  
T. J. George ◽  
J. G. Craig
Keyword(s):  
Pressure Drop ◽  
Specific Gravity ◽  
Area Ratio ◽  
Pneumatic Transport ◽  
Cross Sectional Area ◽  
Pipe Diameter ◽  
Empirical Equations ◽  
Sectional Area ◽  
Cross Sectional ◽  
Pressure Transport

Empirical equations were developed giving minimum air and power requirements for the vacuum and pressure transport of crushed coal through vertical pipelines. Data used in the development were obtained from transport tests in a 50-ft vertical 6-in.-dia pipeline and in a system of 2-, 4-, 6-, and 8-in.-dia horizontal pipelines, each preceded by a short vertical run. The air and power requirements are dependent upon coal rate and specific gravity, upon pipe diameter and length, and upon the ratio of cross-sectional area of the coal pickup section to the pipe. Coal size was not a variable, but the largest lumps could not exceed four-tenths of the pipe diameter. The highest throughput achieved in the 50-ft vertical pipeline was 27 tons per hr of 2-1/2- by 0-in. coal rejects of 2.9 specific gravity. In this experiment with a pickup-to-pipe area ratio of 4.6 to 1, about 1750 actual cu ft per min of air was required at the pipeline entrance to keep the coal moving without floating, and the pressure drop across the pipeline was 2.5 psi. Extrapolation of the equations can be used for designing larger and higher capacity vertical pipeline systems. For example, assuming a pressure drop of 20 psi and a pickup-to-pipe area ratio of 3 to 1, extrapolation indicates 65 tons per hour of 5- by 0-in. coal (sp. gr. 1.40) could be transported through 1000 ft of vertical 12-in.-dia pipe by 7300 actual cu ft of air per min (17,200 standard cu ft per min) at the pipeline entrance at the expense of 1080 theoretical horsepower.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

Changes in the parameters of nasal breathing and parameters of the upper respiratory tract during orthognathic operations in patients with II and III skeletal class of jaw anomalies

2020 ◽  
pp. 22-27
Author(s):  
S.Sh. Gammadaeva ◽  
M.I. Misirkhanova ◽  
A.Yu. Drobyshev
Keyword(s):  
Respiratory Tract ◽  
Nasal Cavity ◽  
Nasal Septum ◽  
Cross Sectional Area ◽  
Upper Respiratory Tract ◽  
Sectional Area ◽  
Nasal Breathing ◽  
Cross Sectional ◽  
Skeletal Class ◽  
Upper Respiratory

The study analyzed the functional parameters of nasal breathing, linear parameters of the nasal aperture, nasal cavity and nasopharynx, volumetric parameters of the upper airways in patients with II and III skeletal class of jaw anomalies before and after orthognathic surgery. The respiratory function of the nose was assessed using a rhinomanometric complex. According to rhinoresistometry data, nasal resistance and hydraulic diameter were assessed. According to the data of acoustic rhinometry, the minimum cross-sectional area along the internal valve, the minimum cross-sectional area on the head of the inferior turbinate and nasal septum and related parameters were estimated. According to the CBCT data, the state of the nasal septum, the inferior turbinates, the nasal aperture, the state of the nasal cavity, and the linear values of the upper respiratory tract (nasopharynx) were analyzed. The patients were divided into 4 groups according to the classification of the patency of the nasal passages by

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