scholarly journals Viscous deformation of relaxing ventricle and pulsatile blood propelling (numerical model)

2014 ◽  
Author(s):  
Yuri Kamnev
Keyword(s):  
Numerical Model ◽  
Volume Flow Rate ◽  
Venous Pressure ◽  
Ventricular Volume ◽  
Volume Flow ◽  
Viscous Deformation ◽  
Operating Range ◽  
Independent Variables ◽  
Dimensional Argument ◽  
Ventricular Filling

AbstractThe numerical model of one-loop circulation exploits viscous deformation as mechanism of ventricular filling. Mathematical advantage of viscous deforming is a possibility to present the ventricular filling as the function of two independent variables (stress and time); two-dimensional argument frames a table which permits to calculate end-diastolic ventricular volume due to information about measured venous pressure and duration of ventricular diastole. The equation was deduced which balances the system while varying of such parameters as arterial resistance, the value of normal rhythm and the volume flow rate. The model pays attention on the phenomenon of asymmetrical position of normal rhythm (the steady rhythm in conditions of rest) and explains why the operating range of brady-rhythms is much narrower than the operating range of tachy-rhythms.

scholarly journals The view of the native gauges of blood pressure - focus on atrium (hydrodynamics and rheology)

2016 ◽  
Author(s):  
Yuri Kamnev
Keyword(s):  
Venous Pressure ◽  
Outer Radius ◽  
Viscoelastic Deformation ◽  
Viscous Deformation ◽  
Specific Distribution ◽  
Component Velocity ◽  
The One ◽  
Coefficient Of Viscosity ◽  
Ventricular Filling ◽  
Velocity Pressure

The precision of the inlet parameters depends on mechanism of response. Reflexes are satisfied with relative higher or lower but if the inlet information is presented by different parameters and the response is calculated according to some equation precision must reach the degree which does not slur over the results of calculation. At recent work the equation for controlling of circulation was suggested where the main inlet parameters are the arterial diastolic and vinous pressures and it becomes pertinent to analyze how organism can perceive these pressures with hydrodynamic accuracy. As far as the velocity pressure component of total pressure can not be detected by wall receptor of the rectilinear section of artery it was noticed that baroreceptors are located at the outer radius of the bend of central arteries and that is justified due to specific distribution of pressure. This phenomenon can be interpreted as a correction of measuring of static pressure with regard for velocity pressure component. Velocity pressure component of venous pressure is comparable with the one of arterial pressure but static components of venous and arterial pressures are incomparable and it is the fact that cannot be ignored when choosing the gauge. The possible method of measuring of pressure is based on observation that pressure-volume vector of the ventricular cycle is similar to a-loop vector of atrial cycle. Ventricular filling vector and x-trough vector show the behavior of viscous material but v-loop inserted into a-loop demonstrates typical viscoelasticity with creep. If viscous deformation of atrium at early relaxation possesses standard duration being stopped by transformation of viscous deformation into viscoelastic deformation the venous pressure can be measured in accordance with the value of viscous deformation. Measuring of pressure by viscous method implemented by atrium has the advantage comparing to measuring by baroreceptor with elastic sensor. Early relaxation of atrium which reveals coefficient of viscosity corresponds to ventricular relaxation and its coefficient of viscosity but the latter is liable to different biochemical shifts. Such shifts influences the atrial coefficient of viscosity either and the values of venous pressure measured by viscous method will be more accurate for calculations because coefficient of viscosity participates in the equation being not estimated in organism.

Novel epoxy/anhydride alternatives for biological electron microscopy: Physical and performance characteristis of embed 812 and LX 112 in combination with NSA/NMA/DMAE

1989 ◽  
Vol 47 ◽  
pp. 1000-1001
Author(s):  
Joe A. Mascorro ◽  
Gerald S. Kirby
Keyword(s):  
Electron Microscopy ◽  
Flow Rate ◽  
Succinic Anhydride ◽  
Volume Flow Rate ◽  
Mass Density ◽  
Uranyl Acetate ◽  
Volume Flow ◽  
Base Resin ◽  
And Performance ◽  
Acid Anhydrides

Embedding media based upon an epoxy resin of choice and the acid anhydrides dodecenyl succinic anhydride (DDSA), nadic methyl anhydride (NMA), and catalyzed by the tertiary amine 2,4,6-Tri(dimethylaminomethyl) phenol (DMP-30) are widely used in biological electron microscopy. These media possess a viscosity character that can impair tissue infiltration, particularly if original Epon 812 is utilized as the base resin. Other resins that are considerably less viscous than Epon 812 now are available as replacements. Likewise, nonenyl succinic anhydride (NSA) and dimethylaminoethanol (DMAE) are more fluid than their counterparts DDSA and DMP- 30 commonly used in earlier formulations. This work utilizes novel epoxy and anhydride combinations in order to produce embedding media with desirable flow rate and viscosity parameters that, in turn, would allow the medium to optimally infiltrate tissues. Specifically, embeding media based on EmBed 812 or LX 112 with NSA (in place of DDSA) and DMAE (replacing DMP-30), with NMA remaining constant, are formulated and offered as alternatives for routine biological work.Individual epoxy resins (Table I) or complete embedding media (Tables II-III) were tested for flow rate and viscosity. The novel media were further examined for their ability to infilftrate tissues, polymerize, sectioning and staining character, as well as strength and stability to the electron beam and column vacuum. For physical comparisons, a volume (9 ml) of either resin or media was aspirated into a capillary viscocimeter oriented vertically. The material was then allowed to flow out freely under the influence of gravity and the flow time necessary for the volume to exit was recored (Col B,C; Tables). In addition, the volume flow rate (ml flowing/second; Col D, Tables) was measured. Viscosity (n) could then be determined by using the Hagen-Poiseville relation for laminar flow, n = c.p/Q, where c = a geometric constant from an instrument calibration with water, p = mass density, and Q = volume flow rate. Mass weight and density of the materials were determined as well (Col F,G; Tables). Infiltration schedules utilized were short (1/2 hr 1:1, 3 hrs full resin), intermediate (1/2 hr 1:1, 6 hrs full resin) , or long (1/2 hr 1:1, 6 hrs full resin) in total time. Polymerization schedules ranging from 15 hrs (overnight) through 24, 36, or 48 hrs were tested. Sections demonstrating gold interference colors were collected on unsupported 200- 300 mesh grids and stained sequentially with uranyl acetate and lead citrate.

Slip And Hall Effects On The Flow Of A Hyperbolic Tangent Fluid Through Porous Medium In A Planar Channel With Peristalsis

GIS Business ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 383-394
Author(s):  
K. Shalini ◽  
K.Rajasekhar
Keyword(s):  
Porous Medium ◽  
Pressure Gradient ◽  
Volume Flow Rate ◽  
Perturbation Technique ◽  
Volume Flow ◽  
Planar Channel ◽  
Hyperbolic Tangent ◽  
Closed Form Solutions ◽  
Long Wavelength ◽  
Hall Effects

In this paper, the effect of Slip and Hall effects on the flow of Hyperbolic tangent fluid through a porous medium in a planar channel with peristalsis under the assumption of long wavelength is investigated. A Closed form solutions are obtained for axial velocity and pressure gradient by employing perturbation technique. The effects of various emerging parameters on the pressure gradient, time averaged volume flow rate and frictional force are discussed with the aid of graphs.

Multi-objective optimization of squirrel cage fan for range hood based on Kriging model

2021 ◽  
pp. 095440622199586
Author(s):  
Qianhao Xiao ◽  
Jun Wang ◽  
Boyan Jiang ◽  
Weigang Yang ◽  
Xiaopei Yang
Keyword(s):  
Flow Rate ◽  
Optimization Design ◽  
Volume Flow Rate ◽  
Kriging Model ◽  
Volume Flow ◽  
Design Parameters ◽  
Multi Objective Optimization ◽  
Nsga Ii ◽  
Multi Objective ◽  
Squirrel Cage

In view of the multi-objective optimization design of the squirrel cage fan for the range hood, a blade parameterization method based on the quadratic non-uniform B-spline (NUBS) determined by four control points was proposed to control the outlet angle, chord length and maximum camber of the blade. Morris-Mitchell criteria were used to obtain the optimal Latin hypercube sample based on the evolutionary operation, and different subsets of sample numbers were created to study the influence of sample numbers on the multi-objective optimization results. The Kriging model, which can accurately reflect the response relationship between design variables and optimization objectives, was established. The second-generation Non-dominated Sorting Genetic algorithm (NSGA-II) was used to optimize the volume flow rate at the best efficiency point (BEP) and the maximum volume flow rate point (MVP). The results show that the design parameters corresponding to the optimization results under different sample numbers are not the same, and the fluctuation range of the optimal design parameters is related to the influence of the design parameters on the optimization objectives. Compared with the prototype, the optimized impeller increases the radial velocity of the impeller outlet, reduces the flow loss in the volute, and increases the diffusion capacity, which improves the volume flow rate, and efficiency of the range hood system under multiple working conditions.

scholarly journals Influence of Magnetic Field on the Peristaltic Flow of a Viscous Fluid through a Finite-Length Cylindrical Tube

2010 ◽  
Vol 7 (3) ◽  
pp. 169-176 ◽  
Author(s):  
S. K. Pandey ◽  
Dharmendra Tripathi
Keyword(s):  
Magnetic Field ◽  
Viscous Fluid ◽  
Transverse Magnetic Field ◽  
Finite Length ◽  
Flow Rate ◽  
Hartmann Number ◽  
Volume Flow Rate ◽  
Critical Value ◽  
Transverse Magnetic ◽  
Volume Flow

The paper presents an analytical investigation of the peristaltic transport of a viscous fluid under the influence of a magnetic field through a tube of finite length in a dimensionless form. The expressions of pressure gradient, volume flow rate, average volume flow rate and local wall shear stress have been obtained. The effects of the transverse magnetic field and electrical conductivity (i.e. the Hartmann number) on the mechanical efficiency of a peristaltic pump have also been studied. The reflux phenomenon is also investigated. It is concluded, on the basis of the pressure distribution along the tubular length and pumping efficiency, that if the transverse magnetic field and the electric conductivity increase, the pumping machinery exerts more pressure for pushing the fluid forward. There is a linear relation between the averaged flow rate and the pressure applied across one wavelength that can restrain the flow due to peristalsis. It is found that there is a particular value of the averaged flow rate corresponding to a particular pressure that does not depend on the Hartmann number. Naming these values ‘critical values’, it is concluded that the pressure required for checking the flow increases with the Hartmann number above the critical value and decreases with it below the critical value. It is also inferred that magneto-hydrodynamic parameters make the fluid more prone to flow reversal. The conclusion applied to oesophageal swallowing reveals that normal water is easier to swallow than saline water. The latter is more prone to flow reversal. A significant difference between the propagation of the integral and non-integral number of waves along the tube is that pressure peaks are identical in the former and different in the latter cases.

Partial Admission, Axial Impulse Type Turbine Design and Partial Admission Radial Turbine Test for SCO2 Cycle

2017 ◽  
Author(s):  
Hyungki Shin ◽  
Junhyun Cho ◽  
Young-Jin Baik ◽  
Jongjae Cho ◽  
Chulwoo Roh ◽  
...  
Keyword(s):  
Axial Force ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Small Diameter ◽  
Volume Flow ◽  
Working Fluid ◽  
Rotating Speed ◽  
Turbo Generator ◽  
Partial Admission ◽  
Reduce Development Time

Power generation cycle — typically Brayton cycle — to use CO2 at supercritical state as working fluid have been researched many years because this cycle increase thermal efficiency of cycle and decrease turbomachinery size. But small turbomachinery make it difficult to develop proto type Supercritical Carbon dioxide (S-CO2) cycle equipment of lab scale size. KIER (Korea Institute of Energy Research) have been researched S-CO2 cycle since 2013. This paper is about 60kWe scale and sub-kWe class turbo generator development for applying to this S-CO2 cycle at the lab scale. A design concept of this turbo-generator is to use commercially available components so as to reduce development time and increase reliability. Major problem of SCO2 turbine is small volume flow rate and huge axial force. High density S-CO2 was referred as advantage of S-CO2 cycle because it make small turbomachinery possible. But this advantage was not valid in lab-scale cycles under 100kW because small amount volume flow rate means high rotating speed and too small diameter of turbine to manufacture it. Also, high inlet and outlet pressure make huge axial force. To solve these problem, KIER have attempt various turbines. In this paper, these attempts and results are presented and discussed.

Numerical Simulation on Air Volume Flow Rate Distribution of Stator Ducts for Salient Pole Synchronous Motor

2014 ◽  
Vol 644-650 ◽  
pp. 373-376
Author(s):  
Li Liu ◽  
Yi Ping Lu ◽  
Jia De Han ◽  
Xue Mei Sun
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Domain Boundary ◽  
Air Flow ◽  
Flow Characteristics ◽  
Synchronous Motor ◽  
Volume Flow ◽  
Rate Distribution ◽  
Salient Pole ◽  
Air Volume

Air volume flow rate distribution of stator ducts along axial and circumferential for salient pole synchronous motor is strongly influenced by the air flow field in the air gap and rotor poles, which is completely different from the flow characteristics of non-salient pole motor and it directly relates to the peak temperature of stator bars and core and axial temperature difference which can affect the safety of the operation. A three-dimensional physical model of 1/8 motor was established and corresponding solution domain boundary conditions were given in this article. The air volume flow rate distribution of stator ducts along axial and circumferential was analyzed based on CFD. The study show that at the same position of the axial stator, the cooling air flow into stator ducts along the circumferential direction is uneven, the air volume flow rate distribution is largely influenced by rotor pole pieces, geometry and position of pole support block and rotor rotation direction.

Identification of Design Criteria for Converter Cooling System of Permanent Magnet Direct-Drive Wind Turbine Generator

2016 ◽  
Author(s):  
Gerardo L. Augusto ◽  
Alvin B. Culaba ◽  
Laurence A. Gan Lim
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Cooling System ◽  
Volume Flow Rate ◽  
Volume Flow ◽  
Design Criteria ◽  
Direct Drive ◽  
Turbine Generator ◽  
Wind Turbine Generator ◽  
System Volume

The design criteria of converter cooling system for a 2.5 MW permanent magnet direct-drive wind turbine generator were investigated. Two (2) distribution networks with pipe sizes of DN40 and DN50 were used as basis for fluid flow analysis. The theoretical system pressure drop and system volume flow rate of converter cooling system were calculated using the governing equations of mass conservation, pump performance curve and distribution network characteristics. The system of nonlinear equations was solved using multivariable Newton-Raphson method with the solution vector determined using LU decomposition method. Numerical results suggest that the DN50 pipe provides a pressure drop limit of less than 300 Pa/m in the converter cooling system better than the pressure drop obtained from a DN40 pipe. The system volume flow rate of DN50 pipe was found to be above the operating limit of heat exchanger requirement of 135.30 L/min which needs to dissipate heat with a minimum of 50 kW.

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