Calculations using CFD are presented for adventitious openings in which the flow is not fully developed. It is shown that the quadratic equation performs significantly better than the power law i.e. a recent claim that the power law equation is preferable to the quadratic equation under such circumstances is not supported. Other recent claims that have been made to support the power law in preference to the quadratic are also examined and reasons are given as to why they are unfounded for conditions of typical, naturally driven air infiltration.
This study is divided into 2 parts : 1. Discussion of the theory of a measurement method for configuration factors using reflections of a curvilinear mirror.2. Estimation method of configuration factors for medium/large scale spaces that can be used instead of methods using the diagrams.
This paper defines a new parameter : the equivalent frequency used for the description of the frequency characteristics of air velocity in turbulent flows.Analyses were performed to identify how much the accuracy of determination of the equivalent frequency depends on the characteristics of the velocity. Results of the analyses identified that the equivalent frequency of the velocity fluctuations in rooms is between 0.1 et 1 Hz, and 90 % of those records were between 0.2 and 0.6 Hz which is the frequency range identified to have most significant impact on people's draught sensation.
Three methods : step-up velocity change, step-down velocity change, and the cut-off frequency method were tested for the dynamic response of two low velocity thermal anemometers.This paper had the objective to identify whether those methods recommended in the standards and guidelines always succeed in determining accurately the frequency response curves and the time constant of low velocities anemometers.
This paper deals with two general approaches used to determine multizone air flow by tracer gas experiments : a tracer gas decay model and a simultaneous release of n different tracer gases in n zones (n x n approach) . The results show a suitable agreement between the model and measurements made, at work-time, in a 3-store building equipped with an hybrid ventilation system.
The deposit of particles on ceilings close to ventilation outlets is mainly caused by the features of mixed ventilation, turbulence and induction. This study aims at solving that annoying problem of particle deposition, for the ventilation industry. The development of a clean outlet is eased thanks to a new experimental approach using an optical technique (in so far as the experimental technique and the CFD calculations are too inefficient).
The paper describes the test procedure and sums up the criteria for the air handling components and systems defined in the Finnish guideline for ventilation equipment Test methods, such as a measuring method of mineral fibres released into airflow, and a method for measuring the odour threshold of processing oils have been added to the guideline.The experience from the labeling system has been very positive .
The author expresses the evaporative efficiency of sweating as a function of wetted skin surface area.This allows to predict mean skin temperature of human body as a function of 4 environmental factors and 2 human factors. With these parameters skin temperature and wettedness for 2 typical cases have been calculated.
A seated, unclothed and bald manikin is used for the experiment. A numerical method calculates the view factors between individual segments of a thermal manikin , and between the outer surfaces and the body segments. The segment to segment radiation is the subject of the research : radiation between segments may be significant and the local differences in radiative heat loss may cause discomfort and cannot be ignored.
This study makes clear that mean skin temperature and skin wettedness do not remain constant but may vary under constant thermal sensations of "slightly warm", "warm" and "hot". The relationship between mean skin temperature and skin wettedness under the constant thermal sensation of "warm" is adequaltely expressed through a convex curve with a negative slope.
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