Introduction.  Chimney-type evaporative  cooling  towers,  widely used  at  large  thermal  and  atomic  power
plants  for  cooling  circulating water  [1 ],  exert  a  substantial  effect  on  their  economic  efficiency  and  ecological
situation in  the  neighborhood of the  plants.  The cooling of water  in  the  tower depends  on many factors,  including
the  aerodynamic conditions of  the  entry  of cold air  into  the  tower  and  the  effect of wind  loading and  the mixing
of external  air  streams  and warm water vapor  in  the  lower part  of  the  tower. We know of attempts  to modify the
existing versions of  the  design of towers with  the  aim of  improving the  efficiency by aerodynamic means  [2 ].
In  order  to  gain  a  thorough  understanding  of  the  processes  taking  place  in  a  tower  and  to  carry  out  a
quantitative  study  of  the  main  aerothermal  processes,  the  present  authors  developed  a  laboratory  model  of  the
chimney-type evaporative cooling tower.  In  this work we present  the basic  results of investigations obtained on  the
laboratory  setup  devised.  Preliminary results were published  in  [3 ].8514
In  a  cooling tower  the  interaction of warm water with cold air  leads  to  the heating of a  steam-air mixture
mainly due  to  the  recondensation of vapor appearing as  a  result of the  evaporation of the warm  circulating water.
Inside  the  tower  the Archimedes  force generates  a  free  convective flow of the warm  vapor-air mixture  containing
micron drops  of water.  The  structure and  intensity of this  flow largely determine  the  efficiency of the  processes of
evaporative cooling  in  such an  installation. For  large modern  towers  the  height H  and  the  diameter of the  base D
are  commensurable  (H/D  ~.  1);  therefore the conditions for intake of air near  the bottom and  escape  in  the upper
part  (with account for the wind speed)  exert a  substantial effect on  the aerodynamic processes  inside  the  tower.  In
turn,  the  aerodynamic processes  have a  very marked  influence on  the processes  of water  evaporation.
As is known  [4,5 ],  to model free connective processes  inside the cooling tower,  in addition to the similarity
between  the  geometric dimensions  of  the model and  the  natural  object  there  should  be  closeness  of  the  physical
similarity numbers  (Rayleigh, Ra,  and  Prandtl,  Pr,  numbers)
Ra  =  flgAT H3/vk,
(1)
Pr  =  v/k,  (2)
where v  is  the  coefficient of kinematic viscosity of a  vapor-air mixture; k  is  the  thermal diffusivity coefficient; g  is
the  free  fall  acceleration;  fl  is  the  temperature  coefficient of volumetric  expansion;  AT  is  the  temperature  drop
between  the heated  air  and  the  surrounding medium. 冷却塔实验室模型英文文献和中文翻译:http://www.youerw.com/fanyi/lunwen_6883.html