The nanoscale liquid sodium film inside the microporous wick structure is of great importance to understanding the evaporation mechanism of the sodium heat pipe. The novel optimized wick structure is made of several l...
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Once-through steam generator (OTSG) is a vital heat transfer equipment of China Fast Reactor-600 (CFR-600), and its startup characteristics are of great importance to the safe operation of nuclear power plant. In this...
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In this study, an advanced experimental system was utilized that incorporated heating, jetting, recycling, and cooling capabilities to ensure the successful execution of stable jet impact experiment that simulating a ...
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In this paper, a discrete unified gas kinetic scheme (DUGKS) with a sparse grid method applied in velocity space (DUGKS-SG) is proposed for simulating rarefied gas flows. The DUGKS-SG decomposes the computationally de...
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In this paper, a discrete unified gas kinetic scheme (DUGKS) with a sparse grid method applied in velocity space (DUGKS-SG) is proposed for simulating rarefied gas flows. The DUGKS-SG decomposes the computationally demanding problem into smaller and independent subproblems, thereby reducing the computational costs and exhibiting good parallelism. Several numerical tests, including the two-dimensional Riemann problem and the lid-driven microcavity flow, have been conducted to validate the performance of the DUGKS-SG. Comparisons with the original DUGKS and the Direct Simulation Monte Carlo (DSMC) method demonstrate that DUGKS-SG can provide satisfactory results with improved efficiency. Specifically, a maximum speedup of 9.486 for a 2D case with 7 CPU cores and 13.035 for a 3D case with 8 CPU cores can be achieved. These results suggest that the proposed DUGKS-SG can serve as an efficient numerical method for rarefied gas flow simulations.
The micro/nanoscale structures on metal surfaces are of significant research interest for boiling heat transfer and exhibit great application potential in the thermal management of high-power electronic devices. This ...
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Owing to potential adverse effects such as fatigue, vibration, scouring, and inherent defects, high-pressure pipelines in chemical processes may fail during operation. After failure, high-energy fluid jets into the su...
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Owing to potential adverse effects such as fatigue, vibration, scouring, and inherent defects, high-pressure pipelines in chemical processes may fail during operation. After failure, high-energy fluid jets into the surrounding space, causing damage to the surrounding equipment and personnel. In extreme cases, the load generated by the jet exerts a reaction force at the pipeline failure point, which causes the pipeline to produce a strong whip, further endangering surrounding systems. To prevent such fundamental and secondary damages, it is important to study the magnitude of the impact force caused by the jetting process and the extent of the impact of the jet cone on surrounding *** this study, an experimental visualization system was utilized that allowed for a continuous and stable heating-jetting-cooling-recovery process for the working fluid. The distance between the nozzle and the impacted target plate can be adjusted on purpose. In this system, deionized water was heated to various conditions (1–8 MPa;20–344 °C) and different states, such as sub-cooled water, two-phase flow, and superheated steam, and then discharged into an atmospheric-pressure environment through pipes of different diameters (2.4–9.2 mm) and length-to-diameter ratios (20–120). Subsequently, the jet cone expanded freely or impacted plates of various sizes and at different distances. Based on the stability and flexibility of this experimental system, new details regarding the jetting process were obtained. Ultimately, a series of experimental data on the jet impact force were obtained, and the expansion morphology of the fluid in the atmospheric-pressure environment was recorded via a high-speed *** experimental results indicate that the water state parameters and the nozzle/pipe structural dimensions significantly affect the shape of the jet cone as well as the magnitude and variation pattern of the jet impact force. Additionally, the jet impact force varies with the distance f
The Liquid Droplet Radiator (LDR), a lightweight frameless radiant heat rejection system, is widely regarded as the optimal heat rejection solution for megawatt-scale space nuclear power systems. The LDR dissipates he...
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Space nuclear reactors possess the inherent benefits of independence from solar energy and the capability to withstand intricate external circumstances. Consequently, the establishment of a dependable automatic contro...
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In this study, an advanced experimental system was utilized that incorporated heating, jetting, recycling, and cooling capabilities to ensure the successful execution of stable jet impact experiment that simulating a ...
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ISBN:
(数字)9798350318821
ISBN:
(纸本)9798350318838
In this study, an advanced experimental system was utilized that incorporated heating, jetting, recycling, and cooling capabilities to ensure the successful execution of stable jet impact experiment that simulating a pipeline complete rupture. High-temperature resistant tempered glass was employed in the experimental system to realize the visibility. During the experiment, 8mm pipes/nozzles of varying lengths were employed as the test sections, and jetting phenomena when the import status is single-phase cold water or two-phase mixture at 0-2MPa were obtained by high-resolution photos. Additionally, the shape of the jet cone and the impact force exerted on the target plate were meticulously analyzed after the working fluid under different state parameters jetting into an atmospheric pressure environment through pipes/nozzles. The research also focused on the variation trend in the magnitude of the jet-impact force, as a function of inlet pressure and temperature, target plate distances, and length-to-diameter ratios. The research findings revealed that cold water(below 100°C), sub-cooled water(above 100°C but not reaching saturation temperature), and two-phase steam-water mixture exhibited distinct jet cone shapes during the jetting process, resulting in varying distributions of the jet force. Furthermore, the distance from the spout to the target plate and the length-to-diameter ratio significantly influenced the magnitude of the jet impact force.
Reliable ignition is a fundamental prerequisite for the scramjet engines. In order to improve the reliability of ignition, further enhance the application of spark ignition in engineering, and improve the ignition abi...
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