The characteristics of the thermal field in the human nasal cavity during the expiration period were investigated using computational fluid dynamics. Heat and water-vapor recovery features were quantitatively investigated under realistic distributions of the epithelial surface and air temperature. A constant expiratory flow rate of 250 mL/s was assumed.

The epithelial surface temperature was approximately 34.3–34.4 °C in the nasopharynx and 33.5–33.6 °C in the vestibule region, and these values are in good agreement with the measurement data in the literature. We observed that heat-recovery from the exhaled air mostly occurred in the posterior turbinate region, and the amount of heat recovered is estimated to be approximately 1/3 of the heat supply during inspiration. Because of this heat transfer from the exhaled air to the epithelial surface, the temperature of the epithelial surface increased in this region, and the exhaled air temperature dropped through the turbinate airway.

Water-vapor recovery primarily occurs in the posterior segments of the turbinates; however, the amount of water-vapor transfer was approximately 1/5 of that in inspiration. Accordingly, the relative humidity of the exhaled air remained constant throughout the airway.

使用计算流体动力学研究了呼气期间人鼻腔内的热场特征。在上皮表面和空气温度的实际分布下，对热量和水蒸气的回收特性进行了定量研究。假定恒定的呼气流速为250 mL / s。

鼻咽中的上皮表面温度约为34.3–34.4°C，前庭区域中的表面温度约为33.5–33.6°C，这些值与文献中的测量数据高度吻合。我们观察到，呼出空气中的热量回收主要发生在后鼻甲区域，回收的热量估计约为吸气期间热量供应的1/3。由于这种从呼出的空气到上皮表面的热传递，上皮表面的温度在该区域中升高，并且呼出的空气温度通过鼻甲气道下降。

水蒸气的回收主要发生在鼻甲的后段。然而，水蒸气的传递量大约是吸气量的1/5。因此，呼气的相对湿度在整个气道中保持恒定。