The nonstationary process of filmwise condensation of vapor on curvilinear fins with condensate suction from interfin grooves is numerically simulated with account taken of surface tension and ...gravity. The problem is reduced to solving a nonlinear evolution equation for the thickness of the condensate film. We performed calculations of the ethanol vapor condensation at atmospheric pressure on the fins of constant curvature for various temperature differences between the fin surface and the vapor saturation and for various values of the rate of condensate suction from the interfin space. Numerical calculations show that the condensation process is stable in the device (i.e., in the condenser) with condensate suction. Filling the interfin space leads to diminishing the zone of intense condensation and reducing the condensate inflow; therefore, this yields stable equilibrium between the condensation and condensate suction. The changes of the condenser temperature at a constant condensate suction entail variation of the filling level of the interfin groove and establishment of a stationary process, provided that the fin temperature becomes constant.
Applying stepwise compressive disturbances of only 1.0 bar from 1.5 to 2.5 bar to a steamwater two-phase medium containing an initial void fraction up to 17%, very strong secondary pressure pulses ...with peaks that could approach 100 bar lasting a few milliseconds were observed to evolve by the impulse of hammer action, in a shock tube type vertical experimental device constituted of a stainless steel pipe of rigid structure, 40 mm inner diameter and about 2.5 m long. The intensity of these secondary shock pulses agreed fairly well with values based on Karplus' theoretical treatment slightly modified. The measured propagation velocity of the primary disturbances showed good agreement with that based on the completely condensed shock wave model proposed by Karplus.
Comparing the present results with those obtained in a preliminary experiment by the present authors, it is concluded that the propagation of the primary shock pulse waves should be distinguished from that of usually considered pressure waves with small amplitude. It is suggested that, from considerations of safety, careful attention should be paid in the design of reactors with a low system pressure-e.g. sodium cooled FBR-to the possibility of such strong secondary pressure pulses being generated by hammer action. Appreciable damage was actually sustained in the experiment by detectors of semiconductor piezo type with 5 mm outer diameter and 10kg/cm
2
rating.
The constructions and operating principles of devices for reducing losses due to evaporation of oil and oil products in the course of loading and unloading operations and transportation of oil and ...oil products are considered. The effectiveness of the proposed system derives from preventing the entry of atmospheric pollutants and moisture into the tank cars, maintenance of the quality of the oil products, increasing the time devoted to cleanout of the storage tanks and tank cars, reducing losses of oil products, and protecting the environment against harmful discharges of vapors of oils and oil products.
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