scholarly journals PENGARUH PENGGUNAAN AIR VENT TUBE TURBULANCE (AVTT) TERHADAP KINERJA MESIN MOTOR MATIK 4 LANGKAH

Bina Teknika ◽  
2017 ◽  
Vol 12 (2) ◽  
pp. 155
Author(s):  
Komarudin Komarudin ◽  
Primson Yohanes
Keyword(s):  
Vent Tube ◽  
Air Vent

Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits

2014 ◽  
Vol 70 (5) ◽  
pp. 871-877 ◽  
Author(s):  
Fahri Ozkan ◽  
M. Cihat Tuna ◽  
Ahmet Baylar ◽  
Mualla Ozturk
Keyword(s):  
Froude Number ◽  
High Speed ◽  
Water Mixture ◽  
High Speed Flow ◽  
Mixture Flow ◽  
Speed Flow ◽  
Aeration Efficiency ◽  
High Head ◽  
Closed Conduit ◽  
Air Vent

Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number.

Application of compact silencers as a noise barrier to a naturally ventilated double-skin façade

2021 ◽  
Vol 69 (3) ◽  
pp. 220-228
Author(s):  
Jeehwan Lee ◽  
Jae D. Chang ◽  
Robert Coffeen
Keyword(s):  
Noise Reduction ◽  
Surface Area ◽  
Natural Ventilation ◽  
Experimental Investigations ◽  
Test Case ◽  
Open Surface ◽  
Low Frequencies ◽  
Noise Barrier ◽  
Double Skin ◽  
Air Vent

A prior study of the acoustical performance of a double-skin facade (DSF) as a noise barrier was carried out based on the percentage of the air vent open surface area, shading louver configurations, and shading louver surface materials. Earlier research findings led to experimental investigations of the acoustical performance capabilities of compact silencers to replace DSF air vents as both noise barriers and air channels because DSF air cavities, which contribute to natural ventilation performance (e.g., wind-driven or buoyancy-driven performance), are acoustically vulnerable to noise transmitted through the air vents. This experimental investigation aims to explore noise reduction (NR) through compact silencers applied to DSF air vents. Double-skin facade mock-up test cases were designed based on three test scenarios of a ventilation open surface area: (1) a 100%air vent open surface area (open mode), (2) a 0% air vent open surface area (closed mode), and (3) a compact silencer. From a data analysis of DSF mock-up test results, the overall NR values of a DSFmock-up ranged from20 to 37 dB(A) depending on the number of compact silencers and the shading louver orientation used. Configurations of compact silencers and shading louvers helped the DSF mock-up achieve additionalNR values of 5 to 10 dB(A) depending on the test case. Moreover, applying compact silencers to a naturally ventilated DSF mock-up led to significant noise reduction at low frequencies (125Hz).

scholarly journals Influence of cross-section geometry on air demand ratio in high-head conduits with radial gate

2021 ◽  
Author(s):  
Alp Bugra Aydin ◽  
Ahmet Baylar ◽  
Fahri Ozkan ◽  
Muhammed Cihat Tuna ◽  
Mualla Ozturk
Keyword(s):  
Froude Number ◽  
Cross Section ◽  
Negative Pressure ◽  
Air Bubbles ◽  
Gate Opening ◽  
Series Of Experiments ◽  
High Head ◽  
Radial Gate ◽  
Cross Section Geometry ◽  
Air Vent

Abstract When the gate of a high-head conduit is partly opened, a negative pressure draws the air in through the air vent. Air that is entrained into the water is instantly forced downstream in the form of air bubbles. When the studies on high-head gated conduits were examined, it was determined that the air demand ratio varied depending on many hydraulic and geometric parameters. This work focused on determining the effect of conduit cross-section geometry on the air-demand ratio. A series of experiments were carried out on high-head radial gated conduits having different cross-section geometries. Experimental results showed that conduit cross-section geometry was an important effect on the air demand ratio especially in small gate opening rates. Further, design equations for the air demand ratio were presented relating the air demand ratio to Froude number, gate opening rate, and ratio of gate opening to conduit length.

scholarly journals PIV Measurements of Ventilation Flow from the Air Vent of a Real Passenger Car

2009 ◽  
Vol 7 (1) ◽  
pp. 3-8
Author(s):  
Jin-Pyung Lee ◽  
Hak-Lim Kim ◽  
Sang-Joon Lee
Keyword(s):  
Passenger Car ◽  
Piv Measurements ◽  
Air Vent

ATP sulfurylase from trophosome tissue of Riftia pachyptila (hydrothermal vent tube worm)

1991 ◽  
Vol 290 (1) ◽  
pp. 66-78 ◽  
Author(s):  
Franco Renosto ◽  
Robert L. Martin ◽  
Jeffrey L. Borrell ◽  
Douglas C. Nelson ◽  
Irwin H. Segel
Keyword(s):  
Hydrothermal Vent ◽  
Riftia Pachyptila ◽  
Atp Sulfurylase ◽  
Vent Tube

Golden ratio air vent holes

2009 ◽  
Vol 126 (1) ◽  
pp. 523
Author(s):  
Akito Takegawa
Keyword(s):  
Golden Ratio ◽  
Air Vent

A Modification of the Standard Weather Bureau Rain Gage for Summer and Winter Use 1

1961 ◽  
Vol 42 (5) ◽  
pp. 311-313
Author(s):  
F. B. Gomm
Keyword(s):  
Laboratory Test ◽  
Field Tests ◽  
Rubber Stopper ◽  
Standard Unit ◽  
Weather Bureau ◽  
Rain Gage ◽  
Collection Tube ◽  
Standard Collection ◽  
Measuring Tube ◽  
Vent Tube

This article describes a modified collection unit for the standard Weather Bureau-type rain gage. The described unit, consisting of a polyethylene bottle, rubber stopper, vent tube and adapter funnel, replaces the metal collection tube of the standard gage. In a laboratory test, evaporation from the modified system was not great enough in a 30-day period to measure with a standard measuring tube. Field tests showed the described unit superior to the standard collection unit and equal to the standard unit with a 0.20-inch oil film in the reduction of evaporation. The described unit, which eliminates recharging with oil or antifreeze after each reading, has been in field use for two years without damage from freezing.

Optimize the Structure of Air Sparger for Stirred Bioreactor

2010 ◽  
Vol 44-47 ◽  
pp. 213-217
Author(s):  
Zhi Wei Zhou ◽  
Bo Yan Song ◽  
Yu Kui Wang ◽  
Zun Tao Li ◽  
Yang Wang
Keyword(s):  
Influence Factors ◽  
Ring Structure ◽  
Ventilation Rate ◽  
Two Phase ◽  
Air Voids ◽  
Stirred Bioreactor ◽  
Whole Process ◽  
The One ◽  
Ventilation Velocity ◽  
Air Vent

During the whole process of cell culture, it needs enough air, especially oxygen supply. Therefore, the research about air sparger became significant. There are many influence factors of air sparger are important, including air sparger structure, installation location, ventilation rate. In order to solve these problems, the finite element numerical calculation is used to set a numerical model of air-liquid two-phase flow. This analysis makes clear that the distance between air vent and the bottom of bioreactor has little effect on the air voids, and the air voids is higher by adopting the structure of single air vent compared with the one of distribution ring structure. But the ventilation structure of big distribution ring avoids flooding effectively. The air voids of bioreactor increased with the velocity of ventilation is increased within limits. However, it causes air incomplete dispersion in bioreactor, overflowing from head top of the liquid, flooding and low air voids, if the ventilation velocity is over speed.

Numerical Simulation on Ghosting Fire in the Confined Underground Space

2014 ◽  
Vol 580-583 ◽  
pp. 2667-2670
Author(s):  
Pei Hong Zhang ◽  
Xiao Wei Lu ◽  
Xiao Ming Zhang
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Source Area ◽  
Confined Space ◽  
Source Areas ◽  
Fire Source ◽  
Underground Fire ◽  
Two Parameters ◽  
Air Vent

The phenomenon of ghosting fire development in underground confined space is simulated to analyze the impacts of ghosting fire generation via some conditions -- different air vent sizes and different fire source areas. FDS is used to establish a physical model of underground fire laboratory in Northeastern University, the simulation is conducted by setting two parameters, the air vent size and the fire source area. The fire heat release rate, temperature, concentration of CO, O2 are measured to analyze the case of ghosting fire generation in underground confined space with different air vent sizes and different fire source areas. It’s most likely to generate ghosting fire when the simulating parameter is that the air vent size is 0.4m × 0.4m and the fire source area is 0.96m2. The conclusion is that increasing the air vent size is not a simple ascending and descending relationship with the occurrence time and duration time of the ghosting fire. Increasing the fire source area can improve the fire heat release rate effectively, and promote the formation of ghosting fire.

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