scholarly journals Impact of Yaw angle on the Effectiveness of an Air Curtain for Solar Cavity Receivers

2020 ◽  
Author(s):  
Elham Alipourtarzanagh ◽  
Alfonso Chinnici ◽  
Zhao Tian ◽  
Graham Nathan ◽  
Bassam Dally
Keyword(s):  
Air Curtain ◽  
Yaw Angle

Conditions for the Effective Use of Air Curtain on Objects of Agricultural Production

2020 ◽  
Vol 67 (1) ◽  
pp. 54-59
Author(s):  
Aleksey V. Kuz’michev ◽  
Stanislav S. Trunov ◽  
Dmitriy A. Tikhomirov
Keyword(s):  
Agricultural Production ◽  
Theoretical Models ◽  
Research Purpose ◽  
Engineering Practice ◽  
Physical Factors ◽  
Air Curtain ◽  
Operating Modes ◽  
Air Jets ◽  
Urgent Task ◽  
Design Characteristics

Creating and maintaining a microclimate in animal housing is an energy-intensive technological process that consumes up to 70 percent of the thermal energy consumed on cattle farms. Improving heating and ventilation systems aimed at reducing energy consumption is an urgent task. (Research purpose) The research purpose is to analyze the theoretical models for calculating air curtains and evaluate the possibility of their use for agricultural production facilities and to identify promising directions in the design solutions for thermal air curtains aimed at rural consumers. (Materials and methods) The article considers the theoretical justification and calculation of air curtains. The authors studied the physical model of interaction of air jets in openings, which serves as the basis for mathematical calculation of air curtains in engineering practice. The article describes the features of using the models for calculating air curtains for agricultural objects and the energy parameters of the curtains depending on the design characteristics and external environmental factors. (Results and discussion) The effect of the air curtain on the energy characteristics of the room has been studied. It was found that it is necessary to determine the type of air curtain that is optimally suitable for protecting the gate opening, with or without heating the air curtain. Authors have found that the engineering methods of calculation are based on different experimental data, which leads to a discrepancy in the results of evaluating the effectiveness of the designed curtain, overestimating its energy intensity and power. The calculation of heat curtains, operating modes should be carried out taking into account the variable effects of external physical factors, the equipment should correspond to a specific room. (Conclusions) The use of air curtains reduces or eliminates the penetration of external cold air into the room through the openings of external gates, requires a smaller volume of air supplied by the curtain, compared to the mass of the incoming air flow.

CFD study of aerodynamic performance of non-pneumatic tyre with hexagonal spokes

2021 ◽  
pp. 095440702110131
Author(s):  
Daksh Bhatia ◽  
Praneeth KR ◽  
Babu Rao Ponangi ◽  
Meghana Athadkar ◽  
Carine V Dsouza
Keyword(s):  
Comparative Study ◽  
Lift Coefficient ◽  
Aerodynamic Performance ◽  
Practical Implementation ◽  
Air Velocity ◽  
Aerodynamic Forces ◽  
Steering Angle ◽  
Camber Angle ◽  
Drag And Lift ◽  
Yaw Angle

Non-pneumatic tyres (NPT) provide a greater advantage over the pneumatic type owing to their construct which increases the reliability of the tyre operation and effectively reduces maintenance involved. Analysing the aerodynamic forces acting on a NPT becomes a crucial factor in understanding it’s suitability for practical implementation. In the present work, the aerodynamic performance of a NPT using CFD tool – SimScale® is studied. This work includes a comparative study of a pneumatic tyre, a NPT with wedge spokes and a NPT with hexagonal spokes (NPT-HS). The effect of air velocity, steering (yaw) angle and camber angle on the aerodynamic performance of the NPT-HS is evaluated using CFD. By increasing the steering angle from 0° to 15°, the lift coefficient decreases by 37% approximately at all velocities. Whereas drag coefficient initially decreases by 21% till 7.5° steering angle and then starts increasing. Increasing camber angle from 0° to 1.5°, both drag and lift coefficients goes on decreasing by approximately 7% and 27% respectively.

Assessment of derailment risk in railway turnouts through quasi-static analysis and dynamic simulation

2021 ◽  
pp. 095440972110240
Author(s):  
Ping Wang ◽  
Jun Lai ◽  
Tao Liao ◽  
Jingmang Xu ◽  
Jian Wang ◽  
...  
Keyword(s):  
Static Analysis ◽  
Dynamic Simulation ◽  
Economic Losses ◽  
Derailment Coefficient ◽  
Straight Line ◽  
Main Track ◽  
Pass Through ◽  
Multi Body ◽  
Yaw Angle ◽  
Curve Radius

Train derailments in railway switches are becoming more and more common, which have caused serious casualties and economic losses. Most previous studies ignored the derailment mechanism when vehicles pass through the turnout. With this consideration, this work aims to research the 3D derailment coefficient limit and passing performance in turnouts through the quasi-static analysis and multi-body dynamic simulation. The proposed derailment criteria have considered the influence of creep force and wheelset yaw angle. Results show that there are two derailing stages in switch panel, which are climbing the switch rail and stock rail, respectively. The 3D derailment coefficient limit at the region of top width 5 mm to 20 mm is much lower than the main track rail, which shows that wheels are more likely to derail in this area. The curve radius before the switch rail is suggested to be set as 350 m. When the curve radius before turnout is 65 m, the length of the straight line between the curve and turnout needs to be larger than 3 m. This work can provide a good understanding of the derailment limit and give guidance to set safety criteria when vehicles pass through the turnout.

Sign in / Sign up

Export Citation Format

Share Document