Yujun Sha

Solar chimney power generation — An experimental research on comprehensive sea water distillation system

This paper has been set up for a small-scale experimental device for solar chimney power generation-sea water desalinization of synthetic system. Through contact temperature measuring devices, we study the temperature rise of internal system, of the glass cover, of heat collector, air temperature rise, variation of water production hourly and changes in the relationship. The results show that water storage can maintain the basic work day and night. The sea water thickness is 80mm of storage water and environmental temperature difference is between 2.5 D and 20 D. Air temperature at the entrance of chimney has a greater improvement comparing to the one at the entrance of heat collector. At 13:00, the greatest improvement of air temperature reaches around 11D and the maximal difference between air temperature and environmental one is up to about 15D. The main output collection of fresh water areas is in the absence of irradiance time. At 20:00 water production arrives at the maximum, 182g/(m2 • h), which reaches the minimum in the strong radiance time, so the efficiency of solar energy in use of the device is above 21.13% Multi-targeted products of synthetic system comparing to the solar chimney power generation system, the efficiency of solar energy in use enhances substantially and to highlight the economic performance at the same time.

Numerical simulation on dimension decrease for annular casing of one centrifugal boiler circulation pump

Primary formulation derivation indicates that the dimension of one existing centrifugal boiler circulation pump casing is too large. As great manufacture cost can be saved by dimension decrease, a numerical simulation research is developed in this paper on dimension decrease for annular casing of this pump with a specific speed equaling to 189, which aims at finding an appropriately smaller dimension of the casing while hydraulic performance and strength performance will hardly be changed according to the requirements of the cooperative company. The research object is one existing centrifugal pump with a diffuser and a semi-spherical annular casing, working as the boiler circulation pump for (ultra) supercritical units in power plants. Dimension decrease, the modification method, is achieved by decreasing the existing casings internal radius (marked as Ri0) while keeping the wall thickness. The research analysis is based on primary formulation derivation, CFD (Computational Fluid Dynamics) simulation and FEM (Finite Element Method) simulation. Primary formulation derivation estimates that a design casings internal radius should be less than 0.75 Ri0. CFD analysis indicates that smaller casing with 0.75 Ri0 has a worse hydraulic performance when working at large flow rates and a better hydraulic performance when working at small flow rates. In consideration of hydraulic performance and dimension decrease, an appropriate casings internal radius is determined, which equals to 0.875 Ri0. FEM analysis then confirms that modified pump casing has nearly the same strength performance as the existing pump casing. It is concluded that dimension decrease can be an economical method as well as a practical method for large pumps in engineering fields.

Numerical Simulations on Assembly Modifications for Annular Casing of One Centrifugal Pump

Centrifugal pumps adopt annular casings instead of volute casings when working in high temperature and high pressure conditions, which results in conservative safety factors in sacrifice of hydraulic efficiency. This paper presents numerical simulations on two assembly modification methods for one annular casing imitating the volute casing to improve hydraulic performance. Method one was the eccentric axis method. Method two was the extended vane method. Numerical simulation results, given by CFX, showed that both the two method could increase the hydraulic efficiency and head while rise in radial force was small.

Unsteady Turbulent Simulation and Analysis of Pressure Fluctuation for High Temperature and High Pressure Centrifugal Pump

The pressure fluctuation in the internal flow passage of centrifugal pump is a key factor affecting the stability of the hydraulic system, especially working at conditions of high temperature and pressure. In this paper, RNG k–e turbulent model is adopted to simulate the unsteady flow through the whole flow passage of centrifugal pump working at temperature T = 300 °C and high pressure P = 280 bar. The pressure fluctuation is calculated at the predefined reference points in the different planes. By analyzing the results, it is found that: 1) the rotor-stator interaction between impeller and diffuser is the main cause for pressure fluctuation; 2) the dominant frequency of pressure fluctuation in the flow passage of impeller is the diffuser passing frequency; 3) the dominant frequency at the points of casing wall is almost the same, and the maximum amplitude is relatively small.Copyright

Experimental study of the influence of seawater depth on solar chimney-sea desalination integrated system

In this paper, three small-scale contrast experimental devices of solar chimney-sea desalination integrated system are set up. Through contact thermometric element and under actual weather conditions, the paper studies the performance influence of seawater depth on solar chimney-sea desalination integrated system. The result shows that too deep water layer will increase the thermal inertia of seawater, and decrease the seawater temperature and reduce the water production of integrated system. From the viewpoint of reducing the thermal inertia, shallower water layer is always much better while ensuring sufficient water for evaporation. On the other hand, the shallower of the water layer, the greater fluctuation of hot air temperature. The temperature difference between hot air currents and the environment can be ensured of being positive when the water depth surpasses certain depth. Therefore, there is an optimized depth of the water layer in the integrated system which is to be further studied.

Solar chimney power generation and analysis for synthetic system performance of sea water desalinization

Aiming at the characteristics and the deficiencies of solar chimney power generation system, analyzing the reasons for the low productive rate of disc-producing solar water distillation, as well as characteristics of sea water, considering that both of them occupy large land resources, so this paper considerably utilizes solar chimney branch of the technical characteristics, cleverly combines together solar chimney power generation technology, solar energy storage technology and solar evaporation with condensation of sea water desalinization, thus, we propose the solar chimney power generation and analysis for synthetic system performance of sea water desalinization. Furthermore, through the theoretical analysis, this synthetic system could improve the whole efficiency of solar energy utilization as well as land resources utilization, at the same time, economic, social and ecological benefits are also rather significant.