Mathematical Modelling of Charge/Discharge Process in Seasonal Heat Storage Tank

The seasonal heat storage tank is the most important component of the SDH （solar district heating） system, which allows significant increase in the share of solar energy in heat supply in comparison with conventional solar systems with short-term accumulation of heat. The adverse impact of their investment sophistication on competitiveness may be compensated by the increased use. For example： Cooperation with heat pump allows to increase the accumulation capacity of the seasonal heat storage tank and causes the direct use of heating energy and accumulation of cooling energy produced by heat pump. In the final stage of the heating period, it can be used to remote cooling supplied buildings. Experimentation on mathematical model is possible to obtain valuable insights about the dynamics of the processes of charging and discharging in the seasonal storage tank and subsequently used in the design, implementation and operation.     

Thermal analysis and phase transformation behaviour during additive manufacturing of Ti–6Al–4V alloy

Despite the fact that the additive manufacturing (AM) technique has been established for almost two decades, its optimisation is still performed by trial and error experimentation. In the present work, a finite element modelling approach was used to study both the temperature distribution and heat flux vector characteristics during multi-layer deposition of a Ti–6Al–4V alloy that take place in the AM process. The results revealed the difference between different powder deposition time intervals on thermal cycles, heat flux vectors and the resulting microstructures. Good agreement between the numerical and experimental results was found. The results obtained can be used for process optimisation.     

The Time Characteristics Making Exact the Screening by Aerodispersion from Smoke Grenade with the Charge Based on Red Phosphorus

The time of ignition τ_r, the time of burning τ_h, and the time of burning-out τ_d at the definite wave length of radiation being attenuated can be determined reliably from time course of attenuation of radiation caused by aerodispersions generated from the smoke protection grenades. In case of grenades being tested containing the smoke mixtures with red phosphorus, the first mentioned time characteristics at the wave length of radiation 10.6 μm were typical by longer values than at the wave length 0.82 μm. With the grenades containing charges of smoke mixture in pressings the maximum attenuation values 0.82 μm were reached at the time of ignition τ_r=3 s, at the wave length 10.6 μm approximately up to τ_r=5 s. The mentioned values of ignition τ_r and the time of burning τ_h make exact the technical data of screening smokes created from the smoke grenades mentioned.