Aerosol diffusiophoresis

Tentative boundary conditions for the containment involve two successive phases. During the first one the containment has an atmosphere temperature around llO C, a humidity ratio near 60 % and with steam condensation onto the condenser surfaces. For good scaling of the volume to surface ratio, the vessel walls are rendered "neutral", as far as condensation is concerned. Condensation, aerosol diffusiophoresis and FP-paint interaction take place on suspended structures called "condenser". V/hen the bundle and circuit transient are over, the circuit is disconnected aerosol deposition and subsequent operation of a washing system transfer FPs to me sump water. This second period duration is 3 days with an atmosphere temperature increase up to 150°C and superheated conditions. This period is devoted to Iodine radiochemistry. 

Waldmann, L., and Schmitt. K. H. (1966) Thermophoresis and Diffusiophoresis of Aerosols. Chapter VI in Davies, C. N. (Ed.) Aerosol Science, Academic, New York. 

To keep the subject matter to manageable proportions. 1 have omitted interesting problems of a specialized nature, such as photophoresis and diffusiophoresis, which are seldom of controlling importance in applied problems. Details of the kinetic theory of aerosols have also been omitted. Although of major importance, they usually enter fully developed, so to. speak, in applications. Besides, their derivation is covered in other books on aerosol science. 

Aerosol particles may also be removed in the clouds by the different phoretic forces, e.g. by diffusiophoresis. This phenomenon involves the motion of particles due to concentration gradient of condensing or evaporating vapour (Goldsmith et al., 1963). In the case of condensation, particles displace towards the drop surface. According to Goldsmith et al. (1963), velocity caused by diffusiophoresis is... 

Derjaguin, B. V., and Yalamor, Y. I. (1972) The theory of thermophoresis and diffusiophoresis of aerosol particles and their experimental testing, in Topics in Current Aerosol Research (Part 2), edited by G. M. Hidy and J. R. Brock. Pergamon, New York, pp. 1-200. 

Goldsmith, P, and May, F. G. (1966) Diffusiophoresis and thermophoresis in water vapor systems in Aerosol Science, edited by C. N. Davies. Academic Press, New York. 

The phoretic processes, thermophoresis and diffusiophoresis, are the deposition processes likely to be susceptible to manipulation by accident management measures. They are of particular interest because unlike many aerosol processes, the phoretic processes are relatively insensitive to aerosol particle size, which will not be known well for the design of accident management strategies. Thermophoresis is the tendency for aerosol particles to move from the hot gas toward a cool surface. The rate of particle deposition is proportional to the gradient in the temperature from the gas to the surface. Accident management efforts that increase this gradient will increase thermophoretic deposition of radionuclide particles in the reactor coolant system. 

The aerosol model In VICTORIA accounts for the following basic mechanisms (1) condensation or evaporation from aerosol particle surfaces (2) deposition onto structural surfaces (3) agglomeration of aerosol particles (4) and transport of aerosols from one cell to another by advection. The deposition mechanisms modeled are gravitational settling, laminar or turbulent deposition. Brownian motion, thermophoresis, diffusiophoresis, and inertial deposition in curved channels (bends). Agglomeration mechanisms include Brownian motion, relative gravitational motion. Interactions In a shear field, and inertia in a turbulent field. 

Aerosol physics during transport is modeled in MELCOR by MAEROS, which includes particle agglomeration and different retention mechanisms including thermophoresis, diffusiophoresis, brownian diffusion and gravitational deposition. Aerosol retention in water pools is of interest in the V-LPIS sequence, when water pools may exists above the ruptured pipe in the auxiliary building it could also be of interest in the water present in the secondary side of steam generators in the SGTR sequence. 

Mineral particles are often found imbedded in precipitating ice particles. These may be associated with the IN, or with the CCN that were involved in the initial droplet formation alternatively, they may be have been scavenged or captured by precipitating particles as they fall through clear air (see, for example, [54] and references therein). In-cloud scavenging occurs via thermophoresis and diffusiophoresis that is, motion of aerosol particles brought about by nonuniform-... 

---