Pressure and Flow Rate Regulation in a Fluid Circulation System Marvin E. Reinecke, Emmerick Guenther and Lewis B. Roof (to Phillips Petrol. Co.) U.S. Pat. 3,240,052 (March 15, 1966)

1966 ◽  
Vol 4 (12) ◽  
pp. 25A-25A
Keyword(s):  
Flow Rate ◽  
Circulation System ◽  
Fluid Circulation ◽  
Rate Regulation

A Cephalopod-Inspired Soft-Robotic Siphon for Thrust Vectoring and Flow Rate Regulation

Soft Robotics ◽  
2020 ◽  
Author(s):  
Runzhi Zhang ◽  
Zhong Shen ◽  
Hua Zhong ◽  
Jiyong Tan ◽  
Yong Hu ◽  
...  
Keyword(s):  
Flow Rate ◽  
Thrust Vectoring ◽  
Rate Regulation

Compliance Effect on the Flow Condition in Vascular In Vitro Experiments

2018 ◽  
Author(s):  
Masami Matsuura ◽  
Simon Tupin ◽  
Makoto Ohta
Keyword(s):  
Flow Rate ◽  
Time Lag ◽  
Flow Patterns ◽  
Poly Vinyl Alcohol ◽  
Circulation System ◽  
Straight Tube ◽  
Flow Conditions ◽  
Flow Properties ◽  
Clinician Training

Endovascular treatment has become the standard for intracranial aneurysm management. In vitro systems including an artery model are required for devices evaluation and clinician training. Although silicone is usually use for such model, its compliance is known to be lower than blood vessels. The purpose of this study was to analyze the influence of model material compliance on flow properties. Silicone and 12 [wt%] poly (vinyl alcohol) hydrogel (PVA-H) were used to create two box-shaped models of significantly different compliance. The inner lumen geometry was a 4 [mm] diameter straight tube (parent vessel) and a 10 [mm] diameter sphere representing the aneurysm. A blood-mimicking fluid made of a mixture of glycerin, water and sodium iodide was used to reproduce the viscosity and density of blood and fit models refractive index. The circulation system consisted of a pulsatile blood pump and resistance valve. A flow rate of 250±50 [ml/min] and pressure from 75 to 115 [mmHg] were set inside the model. Pressure and flow rate sensors were used to monitor flow conditions before and after the model. Particle image velocimetry (PIV) was performed to record the difference of flow patterns inside the aneurysm of both model using a Nd:YAG solid laser system and fluorescent particles. Results revealed a significant change of flow conditions due to model compliance. Attenuation of the flow rate pulse was recorded between the inlet and the outlet of the both model. This attenuation was 51% for PVA-H model. Moreover, a time lag between outlet pressure and outlet flow rate curves was recorded in both model. This time lag was longer with the PVA-H model, as this model exhibit a greater compliance. PIV experiments revealed significant changes of flow patterns and velocity inside the aneurysm. Because of its high compliance, PVA-H model walls moved under the pulsatile conditions. A change of flow direction and decrease of its velocity were observed near the proximal wall of the aneurysm, compared to the silicone model. Such differences might modify the stress on the wall of the aneurysm. To conclude, our experiments revealed that compliance has significant impacts on flow properties and should be taken into account for in vitro vascular model manufacturing.

scholarly journals Analyzing the Energy Efficiency of Fan Systems by Using the Dimensional Analysis (DA) Method

Symmetry ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 537 ◽  
Author(s):  
Gencho Popov ◽  
Kliment Klimentov ◽  
Boris Kostov ◽  
Reneta Dimitrova
Keyword(s):  
Energy Efficiency ◽  
Dimensional Analysis ◽  
Flow Rate ◽  
Energy Use ◽  
Specific Energy Consumption ◽  
Effective Energy ◽  
Frequency Method ◽  
Rate Regulation ◽  
Pipe System ◽  
The Impact

This work represents a method for investigating the energy efficiency of fan systems used to transport fluids. Applying the methods of dimensional analysis (DA) enables establishing five dimensionless complexes ( π criteria), including some basic parameters having impacts on the consumed energy used for the transportation of a unit quantity of air. The proposed criterion π 1 includes the specific energy consumption e v (specific fan power SFP), and is used for the quantitative evaluation of the energy effectiveness of the fluid transportation. This criterion also includes the main geometric size of the pipe system (network) and the gas properties. The criterion π 3 indicates the impact of the applied method of flow rate regulation on the effective energy use of fan systems. This criterion includes parameters characterizing the selected method of flow rate regulation: speed ( n ) for using the frequency method and the referred length ( L T P ) of the pipe system for using the throttle method. The established (proposed) dimensionless parameters are used to study a concrete fan system. The obtained results concerning the evaluation of the impact of the two most used methods of flow rate regulation (frequency and throttle), as well as the density variation as a result of the temperature change, on the effective energy use are graphically presented: π 1 = f ( π 3 ) .

An Experimental Study on Open Natural Circulation Flow Characteristics by Air Injection

2017 ◽  
Author(s):  
Pengjiu Cao ◽  
Xiaxin Cao ◽  
Zhongning Sun ◽  
Ming Ding ◽  
Na Li ◽  
...  
Keyword(s):  
Flow Rate ◽  
Driving Force ◽  
Flow Instability ◽  
Natural Circulation ◽  
Heat Removal ◽  
Air Injection ◽  
Circulation System ◽  
Circulation Flow ◽  
Churn Flow ◽  
Circulation Flow Rate

An open natural circulation system has the characteristics of a simple structure, superior safety performance and strong heat removal capability. However, during long-term operation, the flow instability may occur due to the reduction of the driving force, which will have adverse effects on the heat removal capability and safe operation of the system. Thus, injecting air into the riser is designed in this paper to improve the driving force of the circulation flow, reduce the possibility of flow instability, and increase the heat removal capability. In order to investigate the influence of air injection on the evolution of flow pattern, resistance characteristics and circulation flow rate, the method of visual observation and data analysis is used based on different pore sizes porous media, air injection rate and submergence ratios. The ratio of the driving pressure head to the resistance pressure drop is proposed as the basis for assessing the effect of air injection on the ability of natural circulation. It is found that the driving force of natural circulation increases with the increase of air injection rate, and the circulation flow rate increases obviously when the bubbly flow appears in the riser. However, when the transition from bubbly flow to churn flow appears, the growth of the circulation flow rate slows down because the resistance increases faster than the driving force. Therefore, it can be known that the best performance is obtained when bubbly-churn flow appears in the top of the riser. What’s more, the capacity of lifting water will be reduced and churn flow will appear prematurely when the submergence ratio decreases. This means that in the process of open natural circulation system design, the submergence ratio of the system should be increased as much as possible. Finally, in this paper, it is found that the bubble pump with PS = 0.2 μm has better performance.

Analytical and Experimental Investigation to Determine the Variation of H-W-B Constants for a Scaled Forced Circulation Flat Plate Solar Water Heater

2013 ◽  
Author(s):  
Arunachala Chandavar ◽  
Siddhartha Bhatt ◽  
Sreepathi Krishnamurthy
Keyword(s):  
Mass Flow Rate ◽  
Heat Loss ◽  
Mass Flow ◽  
Flow Rate ◽  
Circulation System ◽  
Absorber Plate ◽  
Forced Circulation ◽  
Solar Water ◽  
Scale Thickness ◽  
Overall Heat Loss Coefficient

Fixed tilt flat plate solar thermal collectors, popularly known as solar water heaters still remain as one of the most interesting technologies for utilization of solar energy. The system performance deteriorates due to scaling because of continuous use of hard water as feed water. The present study deals with the experimental and analytical approach to determine the variation of H-W-B (Hottel–Whillier–Bliss) constants (which compactly represent the efficiency characteristics of a solar water heater) due to variation in solar power input and degree of scaling in case of forced circulation system without considering the variation of input power to the circulating pump. Indoor tests are performed with a copper tube to investigate the flow characteristics. This forms a part of conventional forced circulation system, in place of the usual nine-fin tube array in a full fledged collector. In indoor tests, electrical heating is favored to simulate solar radiation level. Various energy parameters are determined and compared by incorporating the developed numerical code FLATSCALE. Variation between experimental and analytical mass flow rate, overall heat loss coefficient, H-W-B constants with simulated solar radiation level are plotted. In scaled condition, the drop in instantaneous efficiency is due to both scale thickness and reduced water flow rate. Scale thickness acts as an additional thermal conductive resistance between absorber plate and flowing water. Overall heat loss coefficient increases as absorber plate temperature is high during reduced flow rate. The maximum deviation observed is 21.68 % in mass flow rate, 14.64 % in absorber plate mean temperature, 7.86 % in overall heat loss coefficient and 12.04 % in instantaneous efficiency. Compared to a clean tube, a highly scaled tube of 3.7 mm scale thickness indicates a drop of 4.76 % in instantaneous efficiency and 40.28 % in mass flow rate. It is concluded that the growth of scale in forced circulation system does not affect the instantaneous efficiency significantly because of the margin in heat carrying capacity of water inspite of high drop in the flow rate.

Theoretical Analysis of a Natural Circulation System Under Rolling Condition Based on RELAP5/MOD3.3 Code

2013 ◽  
Author(s):  
Haibo Lian ◽  
Hongye Zhu ◽  
Xingtuan Yang ◽  
Shengyao Jiang
Keyword(s):  
Flow Rate ◽  
Natural Circulation ◽  
Large Angle ◽  
Heat Removal ◽  
Circulation System ◽  
Ship Motions ◽  
Rolling Angle ◽  
Empirical Formulas ◽  
Body Forces ◽  
Short Period

Natural circulation is an important process for certain advanced reactor’s main loop and passive heat removal systems. However, in marine conditions the thermo-hydraulic characteristics of natural circulation will change because of the ship motions such as inclination, rolling and heaving, which introduces extra body forces in to the system. In this paper, we conducted theoretical studies on the natural circulation behaviors in a symmetrical two-circuit loop under rolling conditions. A RELAP5/MOD3.3 code is developed based on the basic control equations and empirical formulas. Based on this code the natural circulation behavior under a larger range of rolling angle and period is also investigated. It is found that with the increase of rolling angle and decrease of rolling period, the magnitude of flow fluctuation increases. The fluctuation period of mass flow rate do not always consists with the rolling period under the comprehensive actions of complex body forces. Under the rolling with large angle and short period, the fluctuation period of flow rate is only half the rolling period.

scholarly journals Facile Fabrication of Zeolitic Imidazolate Framework Hollow Fibre Membranes via A Novel Scalable Continuous Fluid Circulation Process

Nanoscale ◽  
2021 ◽  
Author(s):  
Allana Lewis ◽  
Ting Chen ◽  
Fraz Saeed Butt ◽  
Xiuming Wei ◽  
Norbert Radacsi ◽  
...  
Keyword(s):  
Internal Surface ◽  
Hollow Fibre ◽  
Circulation System ◽  
Fluid Circulation ◽  
Zeolitic Imidazolate Framework ◽  
Facile Fabrication

A novel continuous fluid circulation system was designed and employed for the impregnation seeding and fabrication of zeolitic imidazolate framework (ZIF) crystals on the internal surface of polymeric hollow fibre...

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