﻿ 基于STAR-CCM+的某SUV汽车热舒适的研究

# 基于STAR-CCM+的某SUV汽车热舒适的研究Research on Thermal Comfort of an SUV Based on STAR-CCM+

Abstract: Taking an SUV 6-seat pure electric vehicle as the research object, the cold and comfort of the whole vehicle are studied by simulation. The human body model is introduced, and the thermal environ-ment comfort in the passenger compartment is analyzed and evaluated by using PMV-PPD and MAA. The simulation results show that the distribution of cold air velocity and passenger body surface temperature in the cabin is comfortable. Through the analysis of the distribution of evaluation in-dicators, we can clearly understand the distribution of comfort in the passenger compartment, which has the advantages of more cost saving and shorter time effectiveness than the experiment.

1. 引言

2. 模型的建立

2.1. 几何模型及网格划分

2.2. 数学模型

STAR-CCM+中有自带的数值求解器，可以精确模拟车内的热舒适情况。车内空气流速较小，使用k-ε湍流模型，内部流体可看作三维不可压缩流 [14]；乘客舱内的空气为辐射透明介质，符合灰体辐射。求解方程如下：

$\frac{\partial \rho }{\partial t}+\frac{\partial \rho {u}_{i}}{\partial {x}_{i}}=0$ (1)

Figure 1. Curve: system result of standard experiment

Figure 2. Curve: system result of standard experiment

$\frac{\partial \rho {u}_{i}}{\partial t}+\frac{\partial \rho {u}_{i}{u}_{j}}{\partial {x}_{i}}=-\frac{\partial P}{\partial {x}_{i}}+\frac{\partial }{\partial {x}_{j}}\left(\mu \left(\frac{\partial u}{\partial {x}_{j}}+\frac{\partial {u}_{j}}{\partial {x}_{i}}\right)\right)$ (2)

$\frac{\partial \rho T}{\partial t}+\frac{\partial \rho T{u}_{j}}{\partial {x}_{j}}=\frac{\partial }{{c}_{p}\partial {x}_{i}}\left(k\frac{\partial T}{\partial {X}_{i}}\right)$ (3)

3. 边界参数及评价指标

3.1. 边界参数

3.2. 评价指标

3.2.1. PMV-PPD

PMV表示预期平均热感觉，其将舒适状态从冷到热划分为7个等级，见表1。由于环境的舒适性因人体的生理情况不同而异。所以不适人员比例PPD被提出来表达人们对热环境的不满意程度，当PMV在−0.5~0.5时，且PPD < 15%时，人体处于舒适状态。PMV和PPD的计算如式(4)和(5)。

$\text{PMV}=\left[0.028+0.303\mathrm{exp}\left(-0.036M\right)\right]\cdot \left[M-W-{E}_{c}-{E}_{res}-{C}_{res}-H\right]$ (4)

$\text{PPD}=100-95\cdot \mathrm{exp}\left(-0.03353\cdot {\text{PMV}}^{4}-0.2179\cdot {\text{PMV}}^{2}\right)$ (5)

W——人做的机械功，W/m2

${E}_{c}$ ——表皮及出汗的散热量，W/m2

${E}_{res}$ ——呼吸潜热损失量，W/m2

${C}_{res}$ ——呼吸显热损失量，W/m2

H——体表对流和辐射热损失，W/m2

Table 1. Comfort level of PMV evaluation index

3.2.2. 空气龄(MAA)

$\tau =\frac{{\int }_{0}^{\infty }C\left(\tau \right)\text{d}\tau }{{C}_{0}}$ (6)

$C\left(\tau \right)$ ——当以某种特定送风方式送入新鲜空气时测得的示踪气体浓度随时间的变化。

4. 模拟结果分析

4.1. 乘客舱空气流速分布情况

4.2. 乘客舱成员体表温度分布情况

Figure 3. Schematic diagram of air flow line in vehicle

Figure 4. Passenger surface temperature

4.3. 乘客舱平均温度分布

Figure 5. Cross section temperature inside vehicle

4.4. PMV-PPD评价指标分析

Figure 6. PMV distribution on passenger surface

Figure 7. PPD distribution on passenger surface

4.5. 空气龄(MAA)

Figure 8. RH distribution of passenger surface relative humidity

Figure 9. RH distribution of passenger surface relative humidity

5. 总语

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