Computational fluid dynamics (CFD) is adopted to calculate and analyze the performance and separation mechanism of a steam-water separation equipment for a pressurized water reactor (PWR) steam generator. The steam-water two-phase flow is simulated by the Euler two-fluid model, and several representative water droplet diameters are selected among 50 to 400 μm. The influence mechanism of water droplet diameter on the performance is investigated by analyzing the flow parameters such as phase volume fraction, velocity, and turbulent kinetic energy. The results show that the integrated calculation and analysis of the separation equipment can more truly reflect the flow state between the separators, improving the reliability of the performance prediction and mechanism analysis. With the increase in water droplet diameter, the separation efficiency of the separation equipment and each separator gradually increases, the outlet wetness gradually decreases, and the pressure loss first decreases and then stabilizes. When 400 μm is taken as the characteristic value of the actual droplet diameter distribution at the inlet of the separation equipment, the performance prediction is more accurate, the pressure loss of each separator is relatively close, and the pressure loss of the primary separator is less affected by the droplet diameter and smaller than that of the swirl-vane primary separator, which is conducive to achieving a higher circulation ratio (CR). Re-entrainment occurs at the perforations of the primary separator and the outlet of the secondary separator, and the corresponding structure is suggested to be optimized to further improve separation efficiency of the separation equipment.

Printed Circuit Heat Exchangers (PCHEs) are considered an excellent alternative for the main cryogenic heat exchanger of Floating Liquefied Natural Gas (FLNG) facilities due to their compact structure and strong heat transfer performance. However, it is unclear how to configure the geometry of the PCHE channels to achieve its optimal performance in the trans-critical liquefaction process of natural gas (NG), which is critical for the main heat exchanger. In this paper, we numerically studied the thermal-hydraulic characteristics of PCHEs with different channel types under the specified condition. The results elucidate that all channels have an enhancement of heat transfer near the pseudo-critical point of NG. All the wavy channels could improve the heat transfer performance of PCHEs, where the trapezoidal channel achieves the largest promotion. Compared with the straight channel, the local heat transfer coefficient could be increased by up to 53% in the trapezoidal channel. Additionally, vortex appeared at the bends of the wavy channels, which greatly increase the local friction loss. Among several channels, the total pressure drop of zigzag, fillet and the sinusoidal channel was almost the same, while that of the trapezoidal channel was the largest. Furthermore, we compared the comprehensive performance of different types of channels and found that the benefit of heat transfer enhancement could not offset the penalty of flow deterioration. Our work provides important guidance for the design of PCHEs employed in FLNG.

In order to ascertain the impact of working water flow rate and inlet pressure on the performance of the liquid–gas jet pump with square nozzle, the pumping volume ratio and efficiency of the liquid–gas jet pump with square nozzle were experimentally investigated at different inlet pressures and working water flow rates. Furthermore, the internal flow characteristics of the liquid–gas jet pump with square nozzle were explored through the utilization of visualization technology in the self-designed square-nozzle liquid–gas jet pump experimental setup. The findings indicate that the pumping ratio of the liquid–gas jet pump increases in conjunction with an elevation in the inlet pressure. Liquid–gas jet pump efficiency is higher at lower inlet pressures, up to 42.48%, and drops rapidly as inlet pressure increases. The pumping volume ratio of the liquid–gas jet pump increases significantly as the working water flow rate increases, and the working water flow rate exerts a minimal effect on the working efficiency of the liquid–gas jet pump. In the context of extreme vacuum conditions, a considerable number of droplets undergo substantial reflux in the posterior section of the throat, with a notable absence of bubbles in the diffusion tube. The size and number of bubbles diminish gradually along the axial direction. The objective of this paper is to provide a reference point for determining the optimal operational parameters for a square-nozzle liquid–gas jet pump in a practical context.

Intelligent toilets can effectively remove odors and harmful substances from exhaust gases and wastewater, maintaining a fresh and clean indoor atmosphere, which is beneficial to the indoor environment and human health. Currently, research on intelligent toilets conducted by sanitary ware manufacturers is still in its early stages. Many of the intelligent toilets available on the market exhibit issues such as an excessive oscillation amplitude of the cleaning spray bar, premature breakdown of the water column, and inadequate air intake. The present study involves the analysis and redesign of a cleaning spray bar model for intelligent toilets. Additionally, several optimization schemes concerning the flow channel of the cleaning spray bar are proposed in order to enhance the performance of the liquid–air ejector. The computational fluid dynamics (CFD) technique is utilized to analyze the water flow characteristics within the cleaning spray bar of the intelligent toilet and to compare and evaluate the proposed schemes. The calculation results indicate that, for the same inlet flow rate, the optimal structure the block with a length of L = 1.5 mm and the block positioned (4). The swirl numbers of these two optimized models are 14.8% and 8.3% of the protype, respectively, while their air intake is 133% and 131% of the protype, respectively. The optimized solutions exhibited significant performance improvements when compared to the prototype. The computational results offer valuable insights for optimizing the flow characteristics of the enhanced product.