CFD simulations of air curtain dust removal effect by ventilation parameters during tunneling

2020 ◽  
Vol 31 (6) ◽  
pp. 2456-2468 ◽  
Author(s):  
Shuai Yin ◽  
Wen Nie ◽  
Lidian Guo ◽  
Qiang Liu ◽  
Yun Hua ◽  
...  
Keyword(s):  
Dust Removal ◽  
Cfd Simulations ◽  
Air Curtain

scholarly journals Air Curtain Dust Removal Device Design and Dust Prevention Strategy in Heading Face

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Xu Huang
Keyword(s):  
Base Plate ◽  
Dust Concentration ◽  
Prevention Strategy ◽  
Previous Model ◽  
Dust Removal ◽  
Device Design ◽  
Airflow Velocity ◽  
Air Curtain ◽  
Total Dust ◽  
Left And Right

Dust protection is a safety guarantee of heading face. The previous model of air curtain research was ideal, and the dust removal effect was rarely studied in the actual dust-producing face. This paper presents a method of air curtain dust removal (ACDR) in the actual heading face. The author designed an air curtain dust removal device (ACDRD). The law of total dust concentration, respiratory dust concentration, and respiratory dust ratio is obtained. The minimum outlet airflow velocity is analyzed using the flat-plane injection theory. The effect of the exhaust fan placement on the dust removal effectiveness is examined. Research indicates the following: The airflow speed at the upper, left, and right sides of the ∩-shaped slot is 17.39 m/s, 12.04 m/s, and 13.66 m/s, respectively. The minimum dust removal speed of the air curtain is 5.48 m/s. The total dust concentration is the highest in the spot of roadheader operator, and the concentration of respiratory dust decreases sharply within 20 m. When the indentation air duct is 2.1 m away from the base plate, the dust-proof effect is better. The results can provide theoretical bases and methods for air curtain analysis of the heading face.

Active Air Flow Control to Reduce Cavity Receiver Heat Loss

2015 ◽  
Author(s):  
J. Jack Zhang ◽  
John D. Pye ◽  
Graham O. Hughes
Keyword(s):  
Heat Loss ◽  
Thermal Power ◽  
Solar Thermal ◽  
Cfd Simulations ◽  
Air Curtain ◽  
Fluid Physics ◽  
Computational Fluid Dynamics Cfd ◽  
Optimum Velocity ◽  
Solar Receiver ◽  
Good Agreement

Convective air flows are a significant source of thermal loss from tubular cavity receivers in concentrating solar-thermal power (CSP) applications. Reduction in these losses is traditionally achieved by tailoring the cavity geometry, but the potential of this method is limited by the aperture size. The use of active airflow control, in the form of an air curtain, is an established practice to prevent infiltration of cold air through building doorways. Its application in reducing solar receiver convective heat loss is new. In this study, computational fluid dynamics (CFD) simulations are presented for the zero wind case, demonstrating that an optimised air curtain can readily reduce convective losses by more than 45%. A parametric investigation of jet direction and speed indicates that two distinct optimal air curtain flow structures exist. In the first, the jet reduces the size of the convective zone within the cavity by partially sealing the aperture. The optimum velocity range for this case occurs with a low strength jet. At higher jet speeds, the losses are generally set by the flow induced in the cavity and entrainment into the jet. However, a second optimal configuration is discovered for a narrow range of jet parameters, where the entrainment is reduced due to a shift in the stack neutral pressure level, allowing the jet to fully seal the cavity. A physical model is developed, based on the fluid physics of a jet and the ‘deflection modulus’ concept typically used to characterise air curtains in building heating and ventilation applications. The model has been applied to the solar thermal cavity case, and shows good agreement with the computational results.

Numerical Analysis of Smoke Confinement by Means of Air Curtains in High-Rise Buildings

2016 ◽  
Vol 858 ◽  
pp. 287-293 ◽  
Author(s):  
Xiao Tao Zhang ◽  
Chong Tan ◽  
Yu Shi Lu
Keyword(s):  
Pressure Difference ◽  
Critical Pressure ◽  
Discharge Coefficient ◽  
Wind Effect ◽  
Cfd Simulations ◽  
Air Curtain ◽  
High Rise ◽  
Discharge Velocity ◽  
Fire Effect ◽  
Computational Fluid Dynamics Cfd

As an effective approach to confine fire-induced smoke transportation, the application of air curtains is introduced in high-rise buildings during fire. A series of computational fluid dynamics (CFD) simulations were carried out for a full scale corridor in high-rise building, in which different factors such as air curtain discharge velocity (ACDV), human evacuation and pressure difference are considered. The results show that with the ACDV increasing, the smoke flowing resistance of air curtain is greater. The factor of evacuation cause significant impact on the efficiency of air curtain. Compared with the pressure difference caused by wind effect, the fire effect would lead to higher critical pressure difference and discharge coefficient.

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