scholarly journals Flow-Velocity and Pressure Fitness of Sprinkler Pipes Applied with Orifice

2020 ◽  
Vol 20 (5) ◽  
pp. 97-103
Author(s):  
Jaedong Kim ◽  
Youngjae Noh ◽  
Nakseok Kim
Keyword(s):  
Flow Velocity ◽  
Flow Rate ◽  
Fire Suppression ◽  
Water Flow Rate ◽  
Branch Pipe ◽  
Reference Number ◽  
Actual Fire ◽  
Design Value ◽  
Sprinkler Head ◽  
High Building

The sprinkler design of buildings is based on the top-floor end sprinkler head, and the water flow rate and pressure are designed. When the floor is close to the bottom floor pump, unnecessary flow rate, pressure, and flow velocity become inevitable. Moreover, when the sprinkler head is opened to less than the actual fire time reference number, the excessive flow rate, flow velocity, and pressure are generated. Therefore, the damage to the water or droplet particle becomes less significant, which can be disadvantageous for efficient fire suppression. Therefore, in this study, we applied an orifice to the branch pipe of each sprinkler head to decrease the excessive flow rate, flow velocity, and pressure. It was confirmed that the design value was maintained for each floor of the high building. When the orifice was applied, the flow rate and positive well were reduced, which could prevent overpressure.

scholarly journals Study on the Motion Characteristics of Residual Air Mass in Pipelines in Water Transfer Project

2018 ◽  
Vol 246 ◽  
pp. 01113
Author(s):  
Huang Haocheng ◽  
Jiang Jin ◽  
Chen Qi ◽  
Liao Zhifang ◽  
Liu Laiquan
Keyword(s):  
Flow Velocity ◽  
Water Flow ◽  
Flow Rate ◽  
Water Flow Rate ◽  
Water Transfer ◽  
Long Distance ◽  
Water Flow Velocity ◽  
Air Mass ◽  
Motion Characteristics ◽  
Residual Air

For long-distance water transfer projects, the residual air mass in the pipeline will not only reduce the efficiency, but also be detrimental to the safety of the system. In order to study the influence of the water flow velocity of the pressurized water pipeline and the pipeline angle of the hump on the motion characteristics of the residual air mass, an experimental platform with Particle Image Velocimetry (PIV) measuring system was constructed to analyse the flow field. The RSM turbulence model was combined with the VOF multiphase flow model to construct a local high-point gas-liquid two-phase fluid dynamics model for numerical simulation. The results showed that with the increase of water flow velocity, the local hump residual air mass would go through three states, namely, no bubble generation, air bubble was generated and partial discharged, and air mass discharge at one time. If the gas was greater than a certain volume, the increase in the water flow rate required to carry the air mass out of the hump at one time would slow down; the larger the local hump angle was, the greater the water flow rate was required to carry the gas out of the local hump part.

A Numerical Study Onfire Suppression of Water Mist in Microgravity

2014 ◽  
Vol 1016 ◽  
pp. 819-823
Author(s):  
Xue Han ◽  
Jun Qin ◽  
Jun Jun Tao ◽  
Ming Hui Feng
Keyword(s):  
Flow Rate ◽  
Numerical Study ◽  
Fire Suppression ◽  
Water Flow Rate ◽  
Simulation Method ◽  
Critical Value ◽  
Water Mist ◽  
Dominant Mechanism ◽  
Effect Of Water ◽  
Fire Extinguishing

Water mist technology has been developed and regarded as a promising substitute fire-extinguishing agent in spacecraft. In this paper, a numerical simulation method is introduced to investigate the effect of water mist size, velocity and flow rateon the fire suppressionefficiencyin microgravity. The fire extinguishing efficiency is better for the finer water mist in microgravity due to better heat transfer and more rapid vaporization. The evaporation cooling is the dominant mechanism of fire suppression in microgravity.As for the water mist velocity, the performance of fire suppression is affected slightly in microgravity. The results on the effect of water flow rate show that the flow rate should be higher than a critical value to suppress the fire effectively.

scholarly journals Effect of Water Flow on Underwater Wet Welded A36 Steel

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 682
Author(s):  
Eko Surojo ◽  
Aziz Harya Gumilang ◽  
Triyono Triyono ◽  
Aditya Rio Prabowo ◽  
Eko Prasetya Budiana ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Flow ◽  
Flow Rate ◽  
Water Flow Rate ◽  
Physical And Mechanical Properties ◽  
Shielded Metal Arc Welding ◽  
Effect Of Water ◽  
Bending Effect ◽  
Metal Arc Welding ◽  
A36 Steel

Underwater wet welding (UWW) combined with the shielded metal arc welding (SMAW) method has proven to be an effective way of permanently joining metals that can be performed in water. This research was conducted to determine the effect of water flow rate on the physical and mechanical properties (tensile, hardness, toughness, and bending effect) of underwater welded bead on A36 steel plate. The control variables used were a welding speed of 4 mm/s, a current of 120 A, electrode E7018 with a diameter of 4 mm, and freshwater. The results show that variations in water flow affected defects, microstructure, and mechanical properties of underwater welds. These defects include spatter, porosity, and undercut, which occur in all underwater welding results. The presence of flow and an increased flow rate causes differences in the microstructure, increased porosity on the weld metal, and undercut on the UWW specimen. An increase in water flow rate causes the acicular ferrite microstructure to appear greater, and the heat-affected zone (HAZ) will form finer grains. The best mechanical properties are achieved by welding with the highest flow rate, with a tensile strength of 534.1 MPa, 3.6% elongation, a Vickers microhardness in the HAZ area of 424 HV, and an impact strength of 1.47 J/mm2.

On-Line Monitoring System for Monitoring SO2 in Fumes (1) — Monitoring Subsystem for SO2 Mass Concentration

2011 ◽  
Vol 422 ◽  
pp. 296-299
Author(s):  
Shi Long Wang ◽  
Li Na Wang ◽  
Hong Bo Wang ◽  
Yong Hui Cai
Keyword(s):  
Flow Velocity ◽  
Monitoring System ◽  
Flow Rate ◽  
Mass Concentration ◽  
National Monitoring ◽  
Monitoring Result ◽  
Short Period ◽  
On Line ◽  
Working Principle

In order to achieve the target of controlling SO2 emissions in fumes in a short period of time in China, a SO2 on-line monitoring system (CEMS) has been developed by the authorased on the principle of electrochemistry. This system consists of two subsystems: (1) SO2 mass concentration monitoring and (2) SO2 flow velocity and flow rate monitoring. In the paper, the procedure of system and working principle and method of SO2 mass concentration monitoring subsystem are described in detail (SO2 flow velocity and flow rate monitoring subsystem is described by another paper).Two subsystems work synchronously to monitor and calculate the SO2 emissions, then the on-line monitoring of SO2 emissions is achieved. Through experiment and testing, monitoring result of the system is stable and reliable, which has reached the national monitoring standards and passed the appraisal.

scholarly journals Design and thermal characteristic analysis of motorized spindle cooling system

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110208
Author(s):  
Yuan Zhang ◽  
Lifeng Wang ◽  
Yaodong Zhang ◽  
Yongde Zhang
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Thermal Deformation ◽  
Cooling System ◽  
Thermal Characteristic ◽  
Water Flow Rate ◽  
Thermal Characteristics ◽  
Characteristic Analysis ◽  
Motorized Spindle ◽  
Experiment And Simulation

The thermal deformation of high-speed motorized spindle will affect its reliability, so fully considering its thermal characteristics is the premise of optimal design. In order to study the thermal characteristics of high-speed motorized spindles, a coupled model of thermal-flow-structure was established. Through experiment and simulation, the thermal characteristics of spiral cooling motorized spindle are studied, and the U-shaped cooled motorized spindle is designed and optimized. The simulation results show that when the diameter of the cooling channel is 7 mm, the temperature of the spiral cooling system is lower than that of the U-shaped cooling system, but the radial thermal deformation is greater than that of the U-shaped cooling system. As the increase of the channel diameter of U-shaped cooling system, the temperature and radial thermal deformation decrease. When the diameter is 10 mm, the temperature and radial thermal deformation are lower than the spiral cooling system. And as the flow rate increases, the temperature and radial thermal deformation gradually decrease, which provides a basis for a reasonable choice of water flow rate. The maximum error between experiment and simulation is 2°C, and the error is small, which verifies the accuracy and lays the foundation for future research.

Experimental Characterization of a Modified Airlift Pump

2014 ◽  
Author(s):  
Afshin Goharzadeh ◽  
Keegan Fernandes
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
High Speed ◽  
Water Flow Rate ◽  
High Speed Photography ◽  
Two Phase ◽  
Inner Diameter ◽  
Airlift Pump ◽  
Flow Map ◽  
Churn Flow

This paper presents an experimental investigation on a modified airlift pump. Experiments were undertaken as a function of air-water flow rate for two submergence ratios (ε=0.58 and 0.74), and two different riser geometries (i) straight pipe with a constant inner diameter of 19 mm and (ii) enlarged pipe with a sudden expanded diameter of 19 to 32 mm. These transparent vertical pipes, of 1 m length, were submerged in a transparent rectangular tank (0.45×0.45×1.1 m3). The compressed air was injected into the vertical pipe to lift the water from the reservoir. The flow map regime is established for both configurations and compared with previous studies. The two phase air-water flow structure at the expansion region is experimentally characterized. Pipeline geometry is found to have a significant influence on the output water flow rate. Using high speed photography and electrical conductivity probes, new flow regimes, such as “slug to churn” and “annular to churn” flow, are observed and their influence on the output water flow rate and efficiency are discussed. These experimental results provide fundamental insights into the physics of modified airlift pump.

scholarly journals Impacts of Water Flow Rate on Freezing Prevention of Air-Cooled Heat Exchangers in Power Plants

Energies ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 112 ◽  
Author(s):  
Yonghong Guo ◽  
Huimin Wei ◽  
Xiaoru Yang ◽  
Weijia Wang ◽  
Xiaoze Du ◽  
...  
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Power Plants ◽  
Water Flow Rate

scholarly journals Drone Swarms in Fire Suppression Activities: A Conceptual Framework

Drones ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 17
Author(s):  
Elena Ausonio ◽  
Patrizia Bagnerini ◽  
Marco Ghio
Keyword(s):  
Technological Development ◽  
Fire Suppression ◽  
Water Flow Rate ◽  
Cellular Automata Model ◽  
Fire Propagation ◽  
Active Fire ◽  
Fire Front ◽  
Main Factors ◽  
Mediterranean Scrub ◽  
In Fire

The recent huge technological development of unmanned aerial Vehicles (UAVs) can provide breakthrough means of fighting wildland fires. We propose an innovative forest firefighting system based on the use of a swarm of hundreds of UAVs able to generate a continuous flow of extinguishing liquid on the fire front, simulating the effect of rain. Automatic battery replacement and extinguishing liquid refill ensure the continuity of the action. We illustrate the validity of the approach in Mediterranean scrub first computing the critical water flow rate according to the main factors involved in the evolution of a fire, then estimating the number of linear meters of active fire front that can be extinguished depending on the number of drones available and the amount of extinguishing fluid carried. A fire propagation cellular automata model is also employed to study the evolution of the fire. Simulation results suggest that the proposed system can provide the flow of water required to fight low-intensity and limited extent fires or to support current forest firefighting techniques.

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