scholarly journals Dynamic Behavior of Air Void during the Discharge of Cohesive Powder in a Hopper Using a Rubber Air Spring

Fluids ◽  
2021 ◽  
Vol 6 (8) ◽  
pp. 276
Author(s):  
Hideo Kawahara ◽  
Kazuhito Kudo ◽  
Koichiro Ogata
Keyword(s):  
Discharge Rate ◽  
Fluid Pressure ◽  
Maximum Amplitude ◽  
Fine Powder ◽  
Internal Flow ◽  
Solenoid Valve ◽  
Two Phase ◽  
Cohesive Powder ◽  
Gas Interactions ◽  
Opening And Closing

An unstable discharge rate occurs during dry fine powder discharge from a hopper because of the significant two-phase solid/gas interactions that occur in powder flows. In addition, the air bubble phenomenon may occur in a silo during fine powder discharge. In this study, we conducted experiments using a semi-conical dual-structure hopper, and examined the effects on the hopper internal flow structure, cavity fluid pressure, pressure inside the airtight cavity section, and the powder discharge rate when changes are made in the position of the supplied air injection port and the solenoid valve open/close timing. From the experimental results, it was confirmed that an appropriate pressure supply port position exists, and the change in expansion/contraction of the flexible container due to air vibration is determined by the balance between the amount of air inserted and the amount of air discharged, and does not affect the presence or absence of powder so much. Furthermore, as the pressure value in the airtight void is directly related to the change in the expansion and contraction of the flexible container, the maximum amplitude value of the pressure in the airtight void can be kept high and constant at the time of opening and closing the solenoid valve.

Analysis of Single- and Two-Phase Flows in Turbopump Inducers

1967 ◽  
Vol 89 (4) ◽  
pp. 577-586 ◽  
Author(s):  
P. Cooper
Keyword(s):  
Equation Of State ◽  
Flow Field ◽  
Thermal Effects ◽  
Single Phase ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Recent Theory ◽  
Two Phase ◽  
Overall Efficiency

A model is developed for analytically determining pump inducer performance in both the single-phase and cavitating flow regimes. An equation of state for vaporizing flow is used in an approximate, three-dimensional analysis of the flow field. The method accounts for losses and yields internal distributions of fluid pressure, velocity, and density together with the resulting overall efficiency and pressure rise. The results of calculated performance of two sample inducers are presented. Comparison with recent theory for fluid thermal effects on suction head requirements is made with the aid of a resulting dimensionless vaporization parameter.

Fluctuating Forces in U-Tubes Subjected to Internal Two-Phase Flow

2005 ◽  
Author(s):  
Jean-Luc Riverin ◽  
Michel J. Pettigrew
Keyword(s):  
Two Phase Flow ◽  
Periodic Structures ◽  
Internal Flow ◽  
Resonance Phenomenon ◽  
Dimensionless Frequency ◽  
Phase Flow ◽  
Two Phase ◽  
Power Spectral ◽  
Wide Range ◽  
Periodic Components

Severe in-plane vibrations were observed in a series of 20-mm dia. PVC vertical U-tubes of different elbow geometries subjected to air-water internal flow. An experimental study was undertaken to investigate the excitation mechanism. Vibration response, excitation forces and fluctuating properties of two-phase flow were measured over a wide range of flow conditions. The experimental results show that the observed vibrations are due to a resonance phenomenon between periodic momentum flux fluctuations of two-phase flow and the first modes of U-tubes. The excitation forces consist of a combination of narrow-band and periodic components, with a predominant frequency that increases proportionally to flow velocity. For a given void fraction, the force spectra for various flow velocities and elbow geometries coincide generally well on a plot of the normalized power spectral density as a function of a dimensionless frequency. The predominant frequencies of excitation agree with recent results on the characteristics of periodic structures in two-phase flow.

scholarly journals Design and Build Temperature Control and Monitoring in Diesel Engines Using Mobile

2020 ◽  
Vol 10 (1) ◽  
pp. 31-37
Author(s):  
Mohammad Hasan Fuadi
Keyword(s):  
Diesel Engine ◽  
Temperature Control ◽  
Diesel Engines ◽  
Temperature Sensor ◽  
Cooling System ◽  
Cooling Water ◽  
Solenoid Valve ◽  
Valve Opening ◽  
Opening And Closing ◽  
And Control

Diesel engines is generally used for industrial and agricultural machines. Few people care about the engine temperature so it is forced to reach temperature of 100oC, which causes overheating of the diesel engine and has an impact on the performance itself. This also uses a hopper cooling system which is certainly not effective, because it's necessary to see that the water in the reservoir is still or not, also not equipped with an engine temperature display so it's difficult to ascertain the temperature inside. This study aims to monitor and control the temperature of cooling water. Operation of temperature control uses a telecontrol system that is connected to network (Internet of Things) so diesel temperature control can be done remotely. Monitoring of temperature and water level in the reserve tank using Web Mobile. In addition, there is a temperature sensor that is used to measure the temperature of the cooling water so that users can monitor the temperature of the diesel engine on Web Mobile. The test results obtained, the temperature sensor has an average temperature reading error of 0.031004%. Diesel engines with controlled solenoid valve cooling systems can produce ideal temperatures compared to when the solenoid valve is open (using the radiator continuously) or when the solenoid valve is Closed (without using a radiator). When the solenoid is controlled the engine temperature can be ideal because the solenoid valve opening and closing system has the lowest temperature of 56.34oC and the highest temperature of only 80.85oC.

Dynamics of the Internal Flow in Swirl Atomizers by CFD Simulations

2018 ◽  
pp. 100-132
Author(s):  
Roman Ivanovitch Savonov
Keyword(s):  
Numerical Simulation ◽  
Homogeneous Model ◽  
Internal Flow ◽  
Surface Model ◽  
Cfd Simulations ◽  
Two Phase ◽  
Two Phases ◽  
Swirl Atomizer ◽  
Free Surface Model ◽  
Two Fluid

This work presents the simulation of the internal flow in a swirl atomizer. The geometry of the atomizer is calculated by analytical equations used in engineering. The numerical simulation of the two-phase flow is performed by using two equations k-ε turbulence model. The fluids are presented as two-fluid homogeneous model. The interface between two phases is calculated by free surface model. The distribution fields of the axial and tangential velocities, pressures and air core are obtained. The aim of this work is to compare the results obtained by numerical simulation with ones obtained analytically. Also, to study the internal fluids flow inside the atomizer.

Study on Influence of Nozzle Structure on Flow in Diesel Nozzle Orifice

2012 ◽  
Vol 246-247 ◽  
pp. 127-130
Author(s):  
Bing Li ◽  
Xue Song Hu ◽  
Xiao Feng Cao ◽  
Gui Qi Jia ◽  
Fang Xi Xie ◽  
...  
Keyword(s):  
Flow Characteristics ◽  
Internal Flow ◽  
Key Factors ◽  
Complex Flow ◽  
Two Phase ◽  
Nozzle Orifice ◽  
Fuel Flow ◽  
Flow Features ◽  
Diesel Nozzle ◽  
Nozzle Hole

The fuel flow characteristics in diesel nozzle orifice are key factors to the atomization of fuel near the nozzle orifice. In the paper, two-phase flow model is used to simulate the complex flow features in nozzle orifice, and to study the influences of the relative position of nozzles orifice axis and nozzle axis, and inclination angle of nozzle hole on the internal flow feature.

Numerical Analysis of Free Surface Deformation in Water Tank

2003 ◽  
Author(s):  
Fumio Shimizu ◽  
Kiyoshi Hatakenaka ◽  
Kazuhiro Tanaka ◽  
Hiroshi Shigefuji ◽  
Takeshi Shimizu
Keyword(s):  
Free Surface ◽  
Large Scale ◽  
Surface Deformation ◽  
Internal Flow ◽  
Oscillating Flow ◽  
Water Tank ◽  
Loud Noise ◽  
Two Phase ◽  
Free Surface Deformation ◽  
Good Agreement

A siphon phenomenon is one of gas/liquid two-phase flows including free surface deformation. Since the large-scale deformation of the free surface causes a loud noise, it is important to investigate the motion of the free surface. The purpose of the present study is to reproduce a siphon phenomenon in computer, and to analyze an internal flow field of the siphon phenomenon. An oscillating flow in two-dimensional U-tube was simulated to verify our computational codes, and good agreement compared with the theoretical period was obtained. After that, the numerical reproduction of a siphon phenomenon was succeeded and the behavior of the free surface was captured reasonably.

scholarly journals A case study on internal flow patterns of the two-phase closed thermosyphon (TPCT)

2020 ◽  
Vol 18 ◽  
pp. 100586
Author(s):  
S. Sichamnan ◽  
T. Chompookham ◽  
T. Parametthanuwat
Keyword(s):  
Internal Flow ◽  
Flow Patterns ◽  
Two Phase

scholarly journals Numerical analysis of pressure fluctuation in a multiphase rotodynamic pump with air–water two-phase flow

2019 ◽  
Vol 74 ◽  
pp. 18 ◽  
Author(s):  
Wenwu Zhang ◽  
Zhiyi Yu ◽  
Yongjiang Li ◽  
Jianxin Yang ◽  
Qing Ye
Keyword(s):  
Pressure Fluctuation ◽  
Two Phase Flow ◽  
Guide Vane ◽  
Fluid Model ◽  
Pure Water ◽  
Maximum Amplitude ◽  
Phase Flow ◽  
Two Phase ◽  
Rotor Stator Interaction ◽  
Two Fluid Model

Pressure fluctuation in single-phase pumps has been studied widely, while less attention has been paid to research on multiphase pumps that are commonly used in the petroleum chemical industry. Therefore, this study investigates the pressure fluctuation for a multiphase rotodynamic pump handling air–water two-phase flow. Simulations based on the Euler two-fluid model were carried out using ANSYS_CFX16.0 at different Inlet Gas Void Fractions (IGVFs) and various flow rate values. Under conditions of IGVF = 0% (pure water) and IGVF = 15%, the accuracy of the numerical method was tested by comparing the experimental data. The results showed that the rotor–stator interaction was still the main generation driver of pressure fluctuation in gas–liquid two-phase pumps. However, the fluctuation near the impeller outlet ascribe to the rotor–stator interaction was weakened by the complex gas–liquid flow. For the different IGVF, the variation trend of fluctuation was similar along the streamwise direction. That is, the fluctuation in the impeller increased before decreasing, while in the guide vane it decreased gradually. Also, the fluctuation in the guide vane was generally greater than for the impeller and the maximum amplitude appeared in the vicinity of guide vane inlet.

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