高原低气压增氧旅客列车车厢温度场及热舒适的CFD评价

根据青藏铁路格尔木—拉萨段客车增氧低压的环境特点,对人体热舒适评价指标进行修正。基于RNGk—ε模型,采用计算流体动力学软件(CFD),建立25T型客车的简化CFD模型,利用求解该模型获取的数据对乘客热舒适性进行评价。结果表明:靠近车厢内部中央的温度低,靠近四周壁面的高;除车窗附近2个温度测点在大气压强为101.3kPa时的温度线与大气压强为70.7kPa时的有较大差异外,其余4个测点的温度线在这2个大气压强时重合或非常接近;大气压强为101.3和70.7kPa时,6个测点的温度比大气压强为55.6kPa时高0～2℃:在车厢外气温和辐射强度相同的条件下,大气压强下降至55.6kPa时才对车厢内温度产生明显的影响;当大气压强为55.6kPa时,受气流影响,坐在靠近走廊座位且面对来流方向乘客的热舒适性比在大气压强为101.3和70.7kPa时更接近中性,而坐在靠阴面侧壁座位且背对来流方向乘客的热舒适性比在大气压强为70.7kPa时更接近中性;坐在靠近阳面侧壁座位乘客的热舒适性指标为0.1～0.4,介于中性和稍热之间;而坐在其他座位乘客的热舒适性指标为-1.0～-0.6,介于中性和稍冷之间。由此可推断:大气压强和座位在车厢内的位置是影响车厢内乘客热舒适的主要因素。

CFD Evaluation on the Temperature Field and Thermal Comfort of Coach in Low Atmospheric Pressure Passenger Trains with Oxygenation at High Altitudes

Evaluation index of thermal comfort of occupants was corrected according to the environment characteristics of the low atmospheric pressure with oxygenation in the passenger train coach of Qinghai-Tibet Railway from Golmud to Lhasa section.Passengers’ thermal comfort was evaluated by building the simplified 25 T passenger train model with CFD software on the basis of RNG k-ε turbulent model.Results show that,the air temperature near the interior center is lower than that near the surrounding wall surface.There is an obvious temperature difference on the two measuring lines near the window between the atmospheric pressures of 101.3 and 70.7 kPa,while the temperatures of the remaining four measuring lines are coincident or almost the same under such two pressures.When the atmospheric pressure is 101.3 and 70.7 kPa,the temperatures of the six measuring lines are all increased 0.2 ℃ than those of 55.6 kPa,which explains that under the same conditions of outer air temperature and radiation intensity,indoor air temperature is influenced obviously only when the atmospheric pressure is down to 55.6 kPa.When the atmospheric pressure is 55.6 kPa,the thermal sensation is closer to neutral for passengers sitting near the corridor seats facing the airstream than that of both 101.3 and 70.7 kPa,while the thermal sensation is closer to neutral for passengers sitting by the shaded sidewall seats backing the airstream than that of 70.7 kPa.For passengers sitting by the sunny sidewall seats,the thermal sensation is between neutral to slightly hot as the thermal comfort indices of PMV(predicted mean vote) are 0.1,0.4.For other passengers,the thermal comfort sensation is between neutral to slightly cool as the thermal comfort indices of PMV are-1.0～-0.6.It is concluded that the key factors influencing passengers’ thermal comfort are the atmospheric pressure and passenger seat position.