Towards the determination of regional purging flow rate

Abstract This paper deals with the description and determination of the purging flow rate, U p , for ventilation systems or equivalent flow systems. The regional purging flow rate and its use are discussed and proposed. By using the mass conservation principle, U p is embodied in various accessible mathematical expressions in terms of the transfer probability. Some U p -related parameters are described. A Markov chain model is proposed for determining the transfer probability and exploring several useful ventilation indices. An effective CN method is proposed for calculating the interchanging flow rates between various regions. The application of these proposals is demonstrated, and they appear to be promising for analyzing and assessing ventilation performance.

[1]  William Feller,et al.  An Introduction to Probability Theory and Its Applications , 1967 .

[2]  L. T. Fan,et al.  Air flow models in a confined space a study in age distribution , 1969 .

[3]  P. V. Danckwerts.  Continuous flow systems. Distribution of residence times: P. V. Danckwerts, Chem. Engng Sci.2: 1–13, 1953 , 1995 .

[4]  J. Raghuraman,et al.  A markov chain model for residence time and contact time distributions in packed beds , 1975 .

[5]  Mats Sjöberg,et al.  The use of moments for assessing air quality in ventilated rooms , 1983 .

[6]  Mats Sandberg,et al.  The multi-chamber theory reconsidered from the viewpoint of air quality studies , 1984 .

[7]  M. Sandberg.  What is ventilation efficiency , 1981 .

[8]  P. V. Danckwerts.  Continuous flow systems. Distribution of residence times , 1995 .

[9]  F. J. Krambeck,et al.  Stochastic Mixing Models for Chemical Reactors , 1967 .

[10]  L. Cha,et al.  Age distributions for flow systems , 1963, The Canadian Journal of Chemical Engineering.

[11]  Bruce A. Robinson,et al.  Characterization of flow maldistribution using inlet-outlet tracer techniques: An application of internal residence time distributions , 1986 .

[12]  Lars Davidson,et al.  Calculation of age and local purging flow rate in rooms , 1987 .

[13]  Sture Holmberg,et al.  On the Assessment of ventilation Performance with the Aid of Numerical Simulations , 1997 .

[14]  O M LIDWELL,et al.  The evaluation of ventilation , 1960, Journal of Hygiene.

[15]  Y. Zvirin,et al.  Interpretation of internal tracer experiments and local sojourn time distributions , 1976 .

[16]  M. Sandberg.  Ventilation Effectiveness and Purging Flow Rate , 1992 .

[17]  Dudley Brian Spalding,et al.  A note on mean residence-times in steady flows of arbitrary complexity , 1958 .

[18]  M. Sandberg,et al.  Building Ventilation: Theory and Measurement , 1996 .

[19]  C. L. Chiang,et al.  An introduction to stochastic processes and their applications , 1978 .

[20]  K. M. Mehata,et al.  A Markov chain model of a packed bed , 1972 .

[21]  E. Bruce Nauman,et al.  RESIDENCE TIME DISTRIBUTIONS AND MICROMIXING , 1981 .