Xiaoxi Yang

Thermodynamic performance of the NaNO3–NaCl–NaNO2 ternary system

Calculations of phase diagram for additive ternary molten salt system are carried out by the conformal ionic solution theory. The liquidus temperatures of the system NaNO3–NaCl–NaNO2 are determined according to different types of solid–liquid equilibrium and different values of the binary interaction coefficients. For the system NaNO3–NaCl–NaNO2, the calculated and experimental temperatures differ are very small below 673xa0K, but the oxidation and decomposition of the mixed salts are found when the temperature is higher than 673xa0K. Meanwhile, the eutectic point is obtained from calculated phase diagram and the eutectic temperature is 507xa0K. Thermal stability of this eutectic mixture is investigated by thermo-gravimetric analysis device. Experimental results show this kind of molten salt has a lower melting point (501.28xa0K), similar to solar salt (493xa0K). It is thermally stable at temperatures up to 819xa0K, and may be used up to 827xa0K for short periods.

New molten salt heat transfer fluid for solar thermal power plant

In order to remove the oxidation of nitrite salt and reduce the cost of lithium nitrate relative to previously available materials, new molten salt heat transfer fluid (KCl-KNO3-NaNO3) is prepared by static fusion method. Eutectic point and component of molten salt are determined firstly from phase diagram that is calculated by using conformal ionic solution (CIS) theory. Then thermal stability of this mixture is investigated by thermo-gravimetric analysis (DSC-TGA) device. Experimental results show the agreement between measurements and calculations is found to be very good. This kind of molten salt has a lower melting point (210°C), compared to Solar Salt (220°C). It is thermally stable at temperatures up to 500°C, and may be used up to 550°C for short periods. So that was suitable for heat transfer and thermal storage medium.

Numerical Analysis of Packed Bed Structure and the Flow Pressure Drop Using 3D Computer Tomography and Reconstruction Technology

It is known that flow pressure drop in porous media highly depends on the microstructure of solid matrix. Porous structure formed by packed particles, the effect of which on flow pressure drop behavior has been investigated by a series of numerical simulation methods. At the same time, the geometry information of the porous media for the simulations can be obtained by use of the 3D computer tomography and reconstruction technology. Otsu algorithm is introduced to handle the binary edges of the gray, while Amira for generation computing grid. The simulations are in a quite reasonable agreement with the available experimental results, and some further features are also explored. The elongation and the contraction of fluid elements are essential factors for the pressure loss in porous media flow, and the surface friction of micro-channels and the inertial and viscous resistance of the porous media plays important roles in increasing the pressure drop. The value of predicted pressure drop is in a qualitative accordence with the experimental results obtained in previous investigation.Copyright