Anti-icing systems of the mechanical-draft cooling towers

The possibilities of modern anti-icing systems of cooling towers elaborated for sectional and single mechanical-draft towers with irrigation area 144 m² and 400 m² are shown on the basis of the utilization of particularities of aerodynamic conditions in them.     

The influence of discontinuities in elements of a regular packing on their hydraulic resistance

Russian Journal of Applied Chemistry - Results of testing of hydraulic resistance of a regular packing made from vertical corrugated plates are presented. Experiments were carried out in the range...     

Effect of regular nozzles of plastic net on their heat and mass exchange

Results of experiments to determine the number of evaporation in a gravitational liquid film flow on a regular nozzle made in the form of inclined plates of a plastic net with various slopes of the plates in countercurrent water-air system were discussed. Phenomenon of two-way flow of the liquid film on the surface of net parts of the nozzle was established.     

Influence of the diameter of perforation holes on operating indices of irregular heat and mass transfer packing

The influence of the diameter of perforation holes on the operation main indices of irregular metal heat and mass transfer packing is considered.     

An effect of sprinkling density on a value of active surface of irregular heat and mass transfer packing

The results of analysis of an influence of a sprinkling density in the packed columns were reported on a value of an active surface of irregular ring nozzles such as Raschig and Pall rings. Sizes of Raschig rings were 15, 25 and 50 mm; Pall rings, 50 mm. Values of fluid load was 10, 20, 30, 40 and 50 m³ m⁻² h⁻¹). The results of the analysis were presented in graph form.     

New method for detection of exciton Bose condensation using stimulated two-photon emission

An investigation is reported of stimulated two-photon emission by Bose-condensed excitons accompanied by a coherent two-exciton recombination, i.e., by simultaneous recombination of two excitons with opposite momenta leaving unchanged the occupation numbers of exciton states with momenta p≠0. Raman light scattering (RLS) accompanied by a similar two-exciton recombination (or production of two excitons) is also analyzed. The processes under consideration can occur only if a system contains Bose condensate, so their detection can be used as a new method to reveal Bose condensation of excitons. The recoil momentum, which corresponds to a change in the momentum of the electromagnetic field in the processes, is transferred to phonons or impurities. If the recoil momentum is transmitted to optical phonons with frequency ω ₀ ^s , whose occupation numbers are negligible, and the incident light frequency satisfies ω<2Ω, where Ω_=Ω−ω ₀ ^s is the difference frequency and Ω is the light frequency corresponding to the recombination of an exciton with zero momentum, stimulated two-photon emission and RLS with coherent two-exciton recombination give rise to a line at 2Ω_ −ω and an anti-Stokes component at ω+2Ω_, respectively. For ω2Ω_ the RLS spectrum contains Stokes and anti-Stokes components at frequencies ω±2Ω_, whereas stimulated two-photon emission is impossible. Formulas for the cross sections at finite temperatures are obtained for the processes under consideration. Our estimates indicate that a spectral line at 2Ω_−ω, corresponding to the stimulated two-photon emission accompanied by coherent optical phonon-assisted two-exciton recombination can be experimentally detected in Cu₂O. Zh. éksp. Teor. Fiz. 115, 1353–1376 (April 1999)     

Inlet section of hydrodynamic stabilization of flow in a regular nozzle

Russian Journal of Applied Chemistry -