Hongfang Gu

Optimization research on the structure of horizontally-arranged indirect air-cooling tower under strong wind condition

Strong wind has a significant impact on the heat radiation of the air-cooling system. In this research, a numerical calculation model of 2×1000MW horizontally arranged air-cooling tower is established to simulate the flow distribution and heat exchanging capability of three different structures-horizontally-arranged indirect air-cooling tower, tower with guide wall outside, and tower with a cross wall inside-under high-speed wind and extreme-speed wind conditions. The result reveals that the structure with the guide wall outside the tower only works under strong wind condition while the structure with cross wall inside shows the anti-wind capability under both high-speed wind and extreme-speed wind conditions.

Structure Optimization of an Air-Cooling System Platform at a Large Power Plant

The efficiency of cooling units located in an upwind area when the wind blew normal to the platform of an air-cooled condenser (ACC) was usually reduced greatly, and the economy and safety of the ACC were influenced seriously. In this study, a numerical simulation method was used to analyze the structure optimization with an apron wall under the platform for the first time, which was in 2 × 600 MW ACC with a head-on wind direction. The results showed that the optimization effect was obvious with a porous apron wall. At the wind speed of 9 m/s, the hot air recirculation in upwind units was well reduced from the maximum temperature, declining from 15°C to 2°C, and the airflow mass and the face velocity increased well. Especially at the higher wind speed, compared with the board apron wall, the porous apron wall was better in controlling hot air recirculation and improving the performance of whole ACC. Results of this research provided directive theory to solve the problem of row efficiency declining and optimization design.

Experimental and Numerical Investigations on Heat Transfer of Reactor Internals Under Direct Injection

Abstract In a 1250-MW pressurized water reactor (PWR), coolant is injected into the reactor vessel under accident conditions through the method of direct injection, which is the most important function of the emergency core cooling system. Since the problem has been found that safety injection start-up will have a significant thermal effect on the reactor’s internal system, a confirmatory study of an improved structure is required in the initial design stage. In this paper, the heat transfer and flow characteristics of the core barrel, the neutron shielding panels, and the radiation surveillance capsules are investigated by a scaled experiment combined with a numerical method to obtain the distribution of the wall temperature and the convective heat transfer coefficient on the outer wall of the reactor internals under different injection conditions. In addition, potentially dangerous parts have been pointed out, and dimensionless correlations are fitted to describe the heat transfer laws of key parts of reactor internals for use in reactor design. This research fills in the gaps in the study of heat transfer under direct injection of the reactor internals in a PWR, providing support for the safety of the reactor structure.

Investigation on the impact of the environment wind velocity on the indirect air-cooling tower performance

The wind velocity plays a crucial role in the operation characteristic of indirect cooling tower. In this paper a 2×330MW vertical arrangement indirect air-cooled system was taken as research object, and numerical simulation method was used to analyze the relative influence of the wind speed, ranging from 4m/s to 18m/s, on the outlet water temperature of cooling tower, the outlet air temperature of radiator, the facing wind speed of the fan segment and on the outlet air speed of the cooling tower. The result shows that the impact of the natural wind speed on the cooling tower efficiency varies greatly and this impact increases as the wind speed increases.

Experimental study on boiling heat transfer and two-phase frictional pressure drop characteristics of glycol-water solution in a vertical porous surface tube

Although much research has been conducted on investigating the flow boiling heat transfer of low saturation temperature refrigerants, there are few experimental data and theory about the flow boiling heat transfer of high saturation temperature organic mixture which exists widely in the petrochemical industry. To investigate the characteristics of flow boiling heat transfer of high saturation temperature organic mixture, experiments of glycol-water solution flow boiling in a vertical porous surface tube and a vertical smooth tube are conducted. Test tubes are uniformly heated by electrical current with a heated length of 2,000 mm. The mass flux in the experiment ranges from 500 to 1,500t⋅h−1 and the heat flux on test tubes ranges from 10 to 40 kW⋅m−2. The flow boiling heat transfer coefficients and two-phase frictional pressure drops of the two types of tubes are obtained and compared. The results indicate that: the flow boiling heat transfer coefficient in the porous surface tube is 3.8∼5.7 times of that...