Bubble columns are regarded as an effective containment filtration method. A large amount of radioactive aerosol will be retained in a liquid pool and generate decay heat. The surface tension, viscosity and other parameters of the liquid phase are affected by increasing temperature of the liquid pool and the presence of aerosol in the pool, which in turn affect the formation characteristics of bubbles. Another important factor affecting bubble generation characteristics is the proportion of steam in the gas phase, that is, the exchange of mass, and energy of gas phase. This paper will investigate the effects of liquid temperature, aerosol and gas phase composition on bubble formation characteristics by analyzing the variation of bubble detachment volume of the orifice in liquid pool.

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In this paper, experiments were performed to investigate the flow loss characteristics of steam through different microchannels. The microchannels were assembled from stainless steel machined flange assemblies and pipes. The inlet pressure was 20 kPa, and the outlet pressure was adjusted between 5 kPa and 16 kPa (absolute pressure). The steam flow rate in microchannels was obtained by condensing the steam through a condenser coil, and the effects of microchannels of different structures and dimensions on the friction factor were studied by experiment. Experimental results show that the gas flow is not choking, even if the pressure ratio between the inlet and the outlet is as high as 4. In addition, a new correlation between the volumetric flow rate and the pressure difference was derived, and the error between the prediction curve and experimental data is within 20%. Besides, the microchannels’ structure effects on flow loss were investigated. The single most striking observation to emerge from the data comparison was that the gas flow phenomena in grooved channels with different hydraulic diameters were contrary. For microchannels with a hydraulic diameter of 300 µm, higher steam outlet velocities are found when steam flows in specially constructed microchannels. However, the opposite phenomena were observed in microchannels with a hydraulic diameter of 500 µm.

Focused on the problem of unbalanced propellant consumption in parallel tanks of propulsion system, a squeeze-type regulation method based on the gas law method was discussed in the paper. Taking the tank system as the research object, the thermodynamic models under isothermal, adiabatic and other conditions were given and the factors affecting the uncertainty of the model were analysed. The results show that the measurement uncertainty of the model mainly comes from the pressure measurement accuracy and the volume measurement accuracy. The model was applied to different cases and the influence law of different tank parameters on the model uncertainty was studied. It is found that under the premise of the fixed pressure difference of the parallel tanks, the uncertainty of the regulation model is almost linear with the regulation amount. In addition, the relative uncertainty of the model can be reduced effectively by improving the pressure difference of the parallel tanks. The accuracy of the regulation model can reach to 7.7%, which can meet the requirements for on-orbit use.