SA-96-01-1 -- Airflow Characteristics of Jet Expansion for Nonisothermal Flow Conditions PDF

Proper distribution of conditioned air plays an important role in both the comfort of the occupants and the air quality of ventilated or air-conditioned spaces. Air flow patterns and distributions of velocity, temperature, and turbulence intensity are the primary factors that affect room air movement and the comfort of occupants in the occupied zone. However, these factors are dependent upon the characteristics of the diffuser air jet, i.e., expansion, mixing, and entrainment of room air. Therefore understanding the characteristics of the diffuser air jet and its effects on the air flow conditions in the occupied zone is essential to modelling of room air movement and selection and design of air supply outlets. The air flow characteristics at the centreline of the room for 21 test cases under both isothermal and cooling flow conditions were investigated. The main objectives of the study were to present 1) air flow patterns, air velocity, and air temperature and 2) velocity and temperature characteristics of air jet expansion for isothermal and cooling cases in a full-size room using a high sidewall grille. Of the 21 test cases investigated, the normalised profiles of these parameters for eight cases are presented. These cases include both low and high flow rates for four heat load test conditions.

KEYWORDS: year 1996, air flow, properties, rooms, air movement, air flow rate, air temperature, heat load, air quality, temperature distribution, air jets, speed, measuring, calculating