Nonstationary phenomena in the flow section of a vortex compressor

1991 ◽  
Vol 27 (3) ◽  
pp. 157-161
Author(s):  
V. P. Parafeinik ◽  
Yu. A. Bondarenko ◽  
V. I. Reznikov
Keyword(s):  
Flow Section ◽  
Vortex Compressor

A Streamline Curvature Method for Calculating S1 Stream Surface Flow

1984 ◽  
Vol 106 (2) ◽  
pp. 306-312
Author(s):  
S. K. Mao ◽  
D. T. Li
Keyword(s):  
Surface Flow ◽  
Approximation Technique ◽  
Flow Section ◽  
Boolean Expression ◽  
Simple Method ◽  
Stream Surface ◽  
Streamline Curvature ◽  
Calculation Results ◽  
Good Agreement ◽  
Streamline Curvature Method

A streamline curvature method for calculating S1 surface flow in turbines is presented. The authors propose a simple method in which a domain of calculation can be changed into an orderly rectangle without making coordinate transformations. Calculation results obtained on subsonic and transonic turbine cascades have been compared with those of experiment and another theory. Good agreement has been found. When calculating blade-to-blade flow velocity at subsonic speed, a function approximation technique can be used in lieu of iteration method in order to reduce calculation time. If the calculated flow section is of a mixed (subsonic-supersonic) flow type, a Boolean expression obtained from the truth table of flow states is proposed to judge the integrated character of the mixed flow section. Similarly, another Boolean expression is used to determine whether there exists a “choking” of the relevant section. Periodical conditions are satisfied by iterating the first-order derivative of stagnation streamline, which is formed simultaneously. It can be proved that the stagnation streamline formed in this way is unique.

The Effect of Non-Uniform Aerodynamic Loading on the Blade Responses

2007 ◽  
Author(s):  
Abdelgadir M. Mahmoud ◽  
Mohd S. Leong
Keyword(s):  
Turbine Blades ◽  
Forced Response ◽  
Flow Section ◽  
Flow Distortion ◽  
Inlet Flow ◽  
Bladed Disk ◽  
Aerodynamic Loading ◽  
Bladed Disk Assembly ◽  
Flow Generator ◽  
Inlet Flow Distortion

Turbine blades are always subjected to severe aerodynamic loading. The aerodynamic loading is uniform and Of harmonic nature. The harmonic nature depends on the rotor speed and number of nozzles (vanes counts). This harmonic loading is the main sources responsible for blade excitation. In some circumstances, the aerodynamic loading is not uniform and varies circumferentially. This paper discussed the effect of the non-uniform aerodynamic loading on the blade vibrational responses. The work involved the experimental study of forced response amplitude of model blades due to inlet flow distortion in the presence of airflow. This controlled inlet flow distortion therefore represents a nearly realistic environment involving rotating blades in the presence of airflow. A test rig was fabricated consisting of a rotating bladed disk assembly, an inlet flow section (where flow could be controlled or distorted in an incremental manner), flow conditioning module and an aerodynamic flow generator (air suction module with an intake fan) for investigations under laboratory conditions. Tests were undertaken for a combination of different air-flow velocities and blade rotational speeds. The experimental results showed that when the blades were subjected to unsteady aerodynamic loading, the responses of the blades increased and new frequencies were excited. The magnitude of the responses and the responses that corresponding to these new excited frequencies increased with the increase in the airflow velocity. Moreover, as the flow velocity increased the number of the newly excited frequency increased.

scholarly journals The Model for Dilution Process of Landslide Triggered Debris Flow —A Case of Guanba River in Tibet Southeastern Plateau

2018 ◽  
Vol 22 (2) ◽  
pp. 103-111 ◽  
Author(s):  
Jun Li ◽  
Ningsheng Chen
Keyword(s):  
Debris Flow ◽  
Water Flow ◽  
Debris Flows ◽  
Evaluation Model ◽  
Flow Density ◽  
Flow Section ◽  
Average Depth ◽  
Flow Discharge ◽  
Study Results ◽  
Density Evaluation

Understanding and modeling the downstream dilution process of a landslide triggered debris flow is the foundation for recognizing the boundary condition and dilution mechanism of this type of debris flow, and this serves as the theoretical basis for the categorized control of viscous debris flows, diluted debris flows, hyperconcentration flows and flash floods in a drainage basin. In this study, taking as an example a typical debris flow that occurred in the Guanba River on Tibet’s southeastern plateau on July 6th, 1998, empirical models are used to calculate the density, water flow discharge, debris flow discharge, average depth of loose materials and channel gradient at 11 cross-sections upstream to downstream in the debris flow. On this basis, the dilution characteristics and debris flow dilution process are analyzed in this study. According to the correlation between the debris flow density and the water-soil ratio and channel gradient, we have established the density evaluation model for the debris flow dilution process, which can predict the dilution process of a landslide triggered debris flow. The study results include the following four aspects: (1) The key factors in the dilution process of landslide triggered debris flows are the water flow discharge, average depth of loose materials and channel gradient. (2) The debris flow dilution characteristics in the Guanba River in 1998 include the occurrence of the debris flow dilution process after a significant increase in the water-soil ratio; an increase in the proportion of fine particles after dilution of the debris flow; and the size distribution of grain is “narrowed.” (3) In accordance with the density and dilution characteristics, the debris flow dilution process in the Guanba River can be divided into the upstream viscous debris flow section, midstream and downstream transitional debris flow section and downstream diluted debris flow section. (4) The density evaluation model for the debris flow dilution process is expressed by the Lorentz equation, and this model can reflect the debris flow dilution process such that the debris flow density will decrease gradually with an increase in the water-soil ratio and decrease in channel gradient. The density evaluation model for the debris flow dilution process has been verified by three debris flow cases, which include Gaoqiao Gully, Haizi Valley, and Aizi Valley

Square table form internal and external flow section recharge well with filter layer

2015 ◽  
pp. 921-923
Author(s):  
Zhiyuan Yin ◽  
Wanglin Li ◽  
Na Li ◽  
Fang Xu ◽  
Zhengguo Zhao
Keyword(s):  
External Flow ◽  
Flow Section ◽  
Filter Layer ◽  
Recharge Well

scholarly journals Loop flow section conditions of the mixable feed in tilted single-screw batch mixer

2016 ◽  
Vol 16 (1) ◽  
pp. 154-159
Author(s):  
Sergey Braginets- ◽  
Viktor- Hlistunov ◽  
Mihail Chernutskiy ◽  
Anna Tokareva
Keyword(s):  
Flow Section ◽  
Single Screw ◽  
Batch Mixer

A Method for Calculating the Unsaturated Humid Air Flow Section Length in the Mechanical Draft Cooling Tower Sprinkler Channel

Vestnik MEI ◽  
2021 ◽  
pp. 37-43
Author(s):  
Vasiliy Ya. Gubarev ◽  
◽  
Aleksey G. Arzamastsev ◽  
Aleksey I. Sharapov ◽  
Yuliya O. Moreva ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Air Temperature ◽  
Flow Rate ◽  
Cooling Tower ◽  
Initial Conditions ◽  
Air Flow ◽  
Water Flow Rate ◽  
Flow Section ◽  
Transfer Coefficients ◽  
Humid Air

In the channels of mechanical-draft cooling tower sprinklers, a saturated air flow section may appear under certain initial conditions, the mass transfer intensity in which is limited by the steam content in the saturated air. For correctly calculating the heat and mass transfer processes in the cooling tower channel, it is necessary to have a method for determining the unsaturated air flow section length. Publications devoted to studying water cooling processes in the channels of mechanical-draft cooling tower sprinklers do not contain an assessment of the unsaturated air flow section length. A method for determining the unsaturated humid air flow section length in the mechanical-draft cooling tower sprinkler channels is proposed, which is based on the well-known criterion equations for calculating the heat transfer and mass transfer coefficients. The effect the initial air parameters have on the unsaturated air section length is studied, and graphic dependences of the unsaturated air section length are drawn up for each of the analyzed parameters. It is shown that the unsaturated humid air flow section length increases with increasing the initial air temperature. It is also found that the unsaturated air flow section length decreases with a growth in the relative air humidity. An increase in the air flow rate with a constant water flow rate leads to an increase in the unsaturated air flow section length. For the considered sprinkler channel, the saturated air region exists at an air temperature of 15°C and below, and for air temperatures above 25°C there is no saturated air flow section. It is shown that the conclusions drawn about the effect the initial air parameters have on the relative change in the unsaturated air flow section length are valid for channels of various shapes and geometric sizes. The proposed methodology and the results obtained can be used in designing mechanical-draft cooling towers and estimating their efficiency.

Development of vibration system for decreasing of intensity of steel ladle outlet channel tightening

2021 ◽  
Vol 77 (2) ◽  
pp. 165-174
Author(s):  
S. P. Eron’ko ◽  
E. A. Ponamareva ◽  
E. S. Tsykhmistro
Keyword(s):  
Machine Building ◽  
Flow Section ◽  
Steel Ladle ◽  
General View ◽  
Technical Solution ◽  
Test Model ◽  
Outlet Channel ◽  
Hard Particles ◽  
Oscillation Process ◽  
Vibration Impact

The problem of tightening of outlet channel of steel ladle still remains relevant at present. A review of scientific and technical studies, aimed at elaboration of methods to keep the channel flow section constant presented. An analysis of deposition forming mechanisms on walls of outlet channel of steel ladle was done. To prevent their formation it was proposed to apply a vibration impact on the ladle shutter. Using simulation studies and specially elaborated methodology, the degree of influence and frequency of amplitude oscillations, acting along the ladle channel, on increasing speed of layer thickness formation on its walls and number of tearing off hard particles was established. To evaluate intensity of elastic waves absorption by the refractories of ladle shutter during vibration impact on it, a natural experiment was done. As a result of the experiment an initial information was obtained for determining parameters of oscillation process to guarantee effective functioning of the proposed casting facility. A necessity was established to account tenfold decrease of vibration acceleration during propagation of elastic wave along the casting channel from the lower end of collector nuzzle to the upper end of the ladle casting nozzle. Results of the complex studies became base of technical solution at elaboration of design of the ladle shutter. The elaborated shutter is equipped by a system of exciting vertically-directed oscillations, promoting decreasing intensity of hard particles sticking on the walls of the outlet channel. The design of the perfected ladle shutter and general view of its test model shown, which is equipped with the vertically-directed oscillations exciting system. Depending on capacity of the steel ladles, which can be from 100 to 300 t, their shutters can be equipped with one or several pneumatic plunger vibrators. Each of the plunger having the mass of 0.8 kg, can develop an impact force up to 300 N when supplying into its working cavity compressed air of 0.2 MPa pressure at flow rate 150 l/min. Industrial tests of the modernized shutter in a foundry shop of Yasinovatsky machine-building plant were done.

scholarly journals Investigation of the Influence of Liquid Motion in a Flow-based System on an Enzyme Aggregation State with an Atomic Force Microscopy Sensor: The Effect of Water Flow

2020 ◽  
Vol 10 (13) ◽  
pp. 4560 ◽  
Author(s):  
Yuri D. Ivanov ◽  
Tatyana O. Pleshakova ◽  
Ivan D. Shumov ◽  
Andrey F. Kozlov ◽  
Tatyana S. Romanova ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Enzymatic Activity ◽  
Liquid Flow ◽  
Flow Section ◽  
Liquid Motion ◽  
Aggregation State ◽  
Measuring Cell ◽  
Force Microscopy ◽  
Atomic Force ◽  
Solution Studies

The influence of liquid motion in flow-based systems on the aggregation state of an enzyme and on its enzymatic activity was studied, with horseradish peroxidase (HRP) as an example. Our experiments were carried out in a setup modeling the flow section of the biosensor communication with a measuring cell containing a protein solution. Studies were conducted for a biosensor measuring cell located along the axis of a spiral-moving liquid flow. The aggregation state of the protein was determined with an atomic force microscopy-based sensor (AFM sensor). It has been demonstrated that upon flowing of water through silicone biosensor communications, an increased aggregation of HRP protein was observed, but, at the same time, its enzymatic activity did not change. Our results obtained herein are useful in the development of models describing the influence of liquid flow in biosensor communications on the properties of enzymes and other proteins. This is particularly important for the development of serologic protein biosensors, which are beginning to be used for the early diagnosis of oncological diseases (such as brain cancer, prostate cancer, breast cancer etc.). The results obtained herein should also be taken into account when considering possible changes in hemodynamics due to increased protein aggregation.

scholarly journals Design of a Turbulence Generator of Medium Consistency Pulp Pumps

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Hong Li ◽  
Haifei Zhuang ◽  
Weihao Geng
Keyword(s):  
Mathematical Model ◽  
Cfd Simulation ◽  
Liquid Structure ◽  
Flow Fields ◽  
Hydraulic Performance ◽  
Flow Section ◽  
Simple Mathematical Model ◽  
Similar Shape ◽  
Turbulence Generator

The turbulence generator is a key component of medium consistency centrifugal pulp pumps, with functions to fluidize the medium consistency pulp and to separate gas from the liquid. Structure sizes of the generator affect the hydraulic performance. The radius and the blade laying angle are two important structural sizes of a turbulence generator. Starting with the research on the flow inside and shearing characteristics of the MC pulp, a simple mathematical model at the flow section of the shearing chamber is built, and the formula and procedure to calculate the radius of the turbulence generator are established. The blade laying angle is referenced from the turbine agitator which has the similar shape with the turbulence generator, and the CFD simulation is applied to study the different flow fields with different blade laying angles. Then the recommended blade laying angle of the turbulence generator is formed to be between 60° and 75°.

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