Effect of airflow interaction on temperature and velocity at the breathing zone of seated person

The impact of airflow interaction on air temperature and velocity measured at the breathing zone (BZ) of a seated person was studied. A breathing thermal manikin was used to resemble the flow of breathing and the free convection flow (FCF) around the human body. Personalized ventilation (PV) supplied flow from front against the face of the manikin increased the complexity of the interaction.

Experiments were performed in a climate chamber where a quiescent environment was maintained. The chair below the manikin was covered with a local air exhaust called Ventilated Cushion (VC), which aimed to weaken the FCF. The personalized flow was supplied isothermally. The manikin was inhaling through the nose and exhaling through the mouth.

Instruments with short response time were used to measure temperature and velocity. The jet exhaled from the mouth increased the temperature and the velocity at the breathing zone compared to FCF alone. The VC could be used to control the strength of the FCF. The PV flow at 0.4 m/s could penetrate the FCF.

The results indicated that the exhalation flow were dominant to the PV flow.