The traditional research considers that the effective range of forced local ventilation in single head tunnel is the horizontal distance from the jet exit section to the rotary section, but there is a low wind speed a...The traditional research considers that the effective range of forced local ventilation in single head tunnel is the horizontal distance from the jet exit section to the rotary section, but there is a low wind speed area at the end of the range which can not completely and effectively release toxic and harmful gases. In this area, due to the small jet energy, there is no way to effectively remove the toxic and harmful gases produced in the driving process, which seriously affects the safety of the mine.?Therefore, the reasonable definition of the effective range of the forced local ventilation of the single head tunnel can not only improve the theory of the local ventilation of the mine, but also prevent the accumulation of gas and ensure the life safety of the employees. In this paper, the definition of effective range of local ventilation in single head heading face is put forward, and the rationality of the definition of effective range is verified by numerical simulation. On the basis of reasonable definition of effective range, the relationship between wind speed and effective range under different ventilation modes is studied by numerical simulation. The results show that when the wind speed at the outlet of the air duct is less than 20 m/s, the effective range changes rapidly with the outlet wind speed, and after more than 20 m/s, the effect of wind speed on the effective range is gradually weakened. Under the same exit wind speed, the effective range of parallel and coplanar air inlet is much greater than that of single air inlet.展开更多
Based on the analysis of the flying scheme and flying style of an extended range guided munition(ERGM), the aerodynamic characteristics design standards were put forward. According to the standards, the ERGM aerodynam...Based on the analysis of the flying scheme and flying style of an extended range guided munition(ERGM), the aerodynamic characteristics design standards were put forward. According to the standards, the ERGM aerodynamic configuration was designed, and the wind tunnel experiments were processed. The experimental results show that the configuration has lower drag and good static stability at unguided flying stage. Moreover, the stability, maneuverability, rudder deflection angle and balance angle of attack of the configuration are all reasonably matched at guided flying stage, and the munition with the configuration can glide with larger lift-drag ratio at little balance angle of attack. The experimental results also indicate that the canard can't conduct rolling control when 1.0 ＜ Ma ＜ 1.5, so the ERGM must take rolling flight style with certain limited rolling speed.展开更多
文摘The traditional research considers that the effective range of forced local ventilation in single head tunnel is the horizontal distance from the jet exit section to the rotary section, but there is a low wind speed area at the end of the range which can not completely and effectively release toxic and harmful gases. In this area, due to the small jet energy, there is no way to effectively remove the toxic and harmful gases produced in the driving process, which seriously affects the safety of the mine.?Therefore, the reasonable definition of the effective range of the forced local ventilation of the single head tunnel can not only improve the theory of the local ventilation of the mine, but also prevent the accumulation of gas and ensure the life safety of the employees. In this paper, the definition of effective range of local ventilation in single head heading face is put forward, and the rationality of the definition of effective range is verified by numerical simulation. On the basis of reasonable definition of effective range, the relationship between wind speed and effective range under different ventilation modes is studied by numerical simulation. The results show that when the wind speed at the outlet of the air duct is less than 20 m/s, the effective range changes rapidly with the outlet wind speed, and after more than 20 m/s, the effect of wind speed on the effective range is gradually weakened. Under the same exit wind speed, the effective range of parallel and coplanar air inlet is much greater than that of single air inlet.
文摘Based on the analysis of the flying scheme and flying style of an extended range guided munition(ERGM), the aerodynamic characteristics design standards were put forward. According to the standards, the ERGM aerodynamic configuration was designed, and the wind tunnel experiments were processed. The experimental results show that the configuration has lower drag and good static stability at unguided flying stage. Moreover, the stability, maneuverability, rudder deflection angle and balance angle of attack of the configuration are all reasonably matched at guided flying stage, and the munition with the configuration can glide with larger lift-drag ratio at little balance angle of attack. The experimental results also indicate that the canard can't conduct rolling control when 1.0 ＜ Ma ＜ 1.5, so the ERGM must take rolling flight style with certain limited rolling speed.
