Development of the Small Flow Rate Water Hydraulic Servo Valve

2010 ◽  
Vol 22 (3) ◽  
pp. 333-340 ◽  
Author(s):  
Toshiya Watanabe ◽  
◽  
Tomokazu Inayama ◽  
Takeo Oomichi
Keyword(s):  
Flow Rate ◽  
Servo Valve ◽  
Test And Evaluation ◽  
Small Flow Rate ◽  
Hydraulic Servo ◽  
Small Flow ◽  
Hydraulic Manipulator ◽  
Water Hydraulic ◽  
Leakage Characteristics ◽  
Small Capacity

A small capacity servo valve was developed for a small size water hydraulic manipulator, focusing the saving energy. The new servo valve optimizes the machines small flow rate use, makes the stroke longer for wideband use, reduces leakage and makes control easier. The test and evaluation of the servo valve was conducted by examining flow rate characteristics, leakage characteristics and responsibility. The flow rate and leak rate of the servo valve shows to be the same as the oil hydraulic servo valve, while the step and frequency response show good controllability for the water hydraulic manipulator.

scholarly journals Investigation of Speed Matching Affecting Contrarotating Fan’s Performance Using Wireless Sensor Network including Big Data and Numerical Simulation

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hengxuan Luan ◽  
Liyuan Weng ◽  
Ranhui Liu ◽  
Yuanzhong Luan ◽  
Dongmin Li
Keyword(s):  
Big Data ◽  
Numerical Method ◽  
Flow Rate ◽  
Rate Condition ◽  
Small Flow Rate ◽  
Large Flow Rate ◽  
Small Flow ◽  
Power Capability ◽  
Two Stages ◽  
Large Flow

This paper describes the investigations performed to better understand two-stage rotor speed matching in a contrarotating fan. In addition, this study develops a comprehensive measuring and communication system for a contrarotating fan using ZigBee network. The investigation method is based on three-dimensional RANS simulations; the RANS equations are solved by the numerical method in conjunction with a SST turbulence model. A wireless measurement system using big data method is first designed, and then a comparison is done with experimental measurements to outline the capacity of the numerical method. The results show that when contrarotating fan worked under designed speed, performance of two-stages rotors could not be matched as the designed working condition was deviated. Rotor 1 had huge influences on flow rate characteristics of a contrarotating fan. Rotor 2 was influenced by flow rates significantly. Under large flow rate condition, the power capability of rotor 2 became very weak; under working small flow rate condition, overloading would take place to class II motor. In order to solve the performance mismatch between two stages of CRF under nondesigned working conditions, under small flow rate condition, the priority shall be given to increase of the speed of rotor 1, while the speed of rotor 2 shall be reduced appropriately; under large flow rate condition, the speed of rotor 1 shall be reduced and the speed of rotor 2 shall be increased at the same time.

Thermal Flow Sensors for Very Small Flow Rate

2001 ◽  
pp. 1436-1439 ◽  
Author(s):  
M. Ashauer ◽  
H. Scholz ◽  
R. Briegel ◽  
H. Sandmaier ◽  
W. Lang
Keyword(s):  
Flow Rate ◽  
Thermal Flow ◽  
Flow Sensors ◽  
Small Flow Rate ◽  
Small Flow

Behavior of Secondary Flow in a Low Solidity Tandem Cascade Diffuser

2012 ◽  
Author(s):  
Daisaku Sakaguchi ◽  
Hironobu Ueki ◽  
Masahiro Ishida ◽  
Hiroshi Hayami
Keyword(s):  
Secondary Flow ◽  
Flow Rate ◽  
Flow Separation ◽  
Lift Coefficient ◽  
Pressure Recovery ◽  
Suction Surface ◽  
Flow Rates ◽  
Blade Loading ◽  
Small Flow Rate ◽  
Small Flow

Low solidity circular cascade diffuser abbreviated by LSD was proposed by Senoo et al. showing a high blade loading or a high lift coefficient without stall even under small flow rate conditions. These high performances were achieved by that the flow separation on the suction surface of the LSD blade was successfully suppressed by the secondary flow formed along the side walls. The higher performance of the LSD was achieved in both pressure recovery and operating range by adopting the tandem cascade because the front blade of the tandem cascade was designed suitably for small flow rates while the rear blade of the tandem cascade was designed suitably for large flow rates. In order to clarify the reason why the tandem cascade could achieve a high pressure recovery in a wide range of flow rate, the flow in the LSD with the tandem cascade is analyzed numerically in the present study by using the commercial CFD code of ANSYS-CFX 13.0. The behavior of the secondary flow is compared between the cases with the single cascade and the tandem one. It is found that the high blade loading of the front blade is achieved at the small flow rate by formation of the favorable secondary flow which suppresses the flow separation on suction surface of the front blade, and the flow separation on pressure surface of the front blade appeared at the design flow rate can be suppressed by the accelerated flow in the gap between the trailing edge of the front blade and the leading edge of the rear blade, resulting in the positive lift coefficient in spite of a large negative angle of attack.

scholarly journals Numerical Study of the Air Ingress Accident of the HTR-PM and Possible Mitigation Measures

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Wei Xu ◽  
Han Zhang ◽  
Heng Xie ◽  
Lei Shi ◽  
Jun Sun
Keyword(s):  
Flow Rate ◽  
Numerical Study ◽  
Reactor Core ◽  
Mitigation Measures ◽  
Injection Velocity ◽  
Primary Circuit ◽  
Small Flow Rate ◽  
Small Flow ◽  
Hypothetical Accident ◽  
Air Ingress

The double-ended guillotine break (DEGB) of the horizontal coaxial gas duct of a high-temperature gas-cooled reactor is an extremely hypothetical accident, which could cause the air to enter into the primary circuit and react with graphite in the reactor core. The performance of the HTR-PM plant under this extremely hypothetical accident has been studied by the system code TINTE in this work. The results show that the maximum fuel temperature will not reach the temperature design limitation, and the graphite oxidation will not cause unacceptable consequences even under some conservative assumptions. Moreover, nitrogen and helium injected from the fuel charging tube were studied as the possible mitigation measures to further alleviate the consequences of this air ingress accident. The preliminary results show that only the flow rate of nitrogen injected reaches a certain value, which can effectively alleviate the consequences, while for helium injection, both high and small flow rate can prevent or cut off the natural circulation and alleviate the consequences. The reason is that helium is much lighter than nitrogen, and the density difference between the coolant channel and the reactor core is small when helium is injected. Considering the injection velocity, the total usage amount, and the start time of gas injection, helium injected with a small flow rate is suggested.

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