In particle image velocimetry (PIV) experiments, background noise inevitably exists in the images when a is being captured or transmitted, which blurs image, reduces information entropy of and finally makes obtained flow field inaccurate. Taking low-quality original as research object this research, frequency domain processing method based on wavelet decomposition reconstruction was applied to perform pre-processing. Information analysis used evaluate effect processing. The results showed...

The maldistribution of fluid flow through multi-channels is a critical issue encountered in many areas, such as multi-channel heat exchangers, electronic device cooling, refrigeration and cryogenic devices, air separation the petrochemical industry. In this paper, uniformity distribution printed circuit exchanger (PCHE) investigated. resistance characteristics PCHE plate are studied with numerical models under different cases. results show that sudden change angle at inlet channel can be...

This paper studies the event-triggered H∞ control problem for networked switched systems with a mixed time and state-dependent switching law. By event-triggering strategies, only necessary samplings of feedback signals are determined to be released. The advantages that redundant transmissions updates can reduced. adopted law, each sub-system will work minimum dwell time, then starts work. Specifically, by using discrete strategies considering effects transmission delays, time-delay...

3D non-equilibrium molecular dynamics simulations are performed to investigate the friction heat dissipation and generation of high-speed sliding system. A simulation model with two blocks is built. The different materials, velocities studied. mechanism at interface investigated. partition system obtained. results show that more will be produced higher velocity. But in case plastic deformation, less generated. mainly influenced by material velocity ratio. which has similar thermodynamic...

An experimental investigation of single-phase and two-phase (evaporation condensation) heat transfer pressure drop characteristics is performed for five micro-fin tubes with various geometries using refrigerant R22 as the working fluid. The mass flux in range 130–550 kg/m2s. Evaporation tests are conducted at 6 °C saturation temperature, 0.1 inlet quality 0.9 outlet quality, while condensation carried out 45 0.8 quality. results suggest that coefficients increased by 46.3%–63.6% compared to...

The condition monitoring of the feedwater pump in secondary circuit is critical to safe operation nuclear power plant. This article presents a fault diagnosis method by using parameter-optimized support vector machine (SVM). While features are reflected from spectrum vibration signals, we trained and diagnosed feature table with machine. optimal penalty factor C kernel parameter γ selected grid search k-fold cross validation. Then faults SVM model under parameters. Diagnostic results show...

When the ship runs, owing to superposition of gravity shaft and resistance water, with increment in rotational speeds, will produce different degrees bending deformation, which immensely reduces power transmission efficiency. Based on aforementioned problem, present study focuses influences deformation a cavitation effect dynamic characteristics stern bearing. The mixed lubrication model is established. At present, deflection curve equation employed, finite perturbation method applied...

Considering the complexity of three-dimensional environment and flexibility quadrotor aircraft, using traditional A* algorithm for global path planning has disadvantages less search direction, more expanded nodes, a longer path. Therefore, an improved is proposed, which from two aspects. Firstly, two-layer extended neighborhood strategy can increase direction make better use aircraft. Secondly, heuristic function to value closer actual distance, reduce expansion nodes optimize Finally,...

In order to obtain the influence of structural parameters pin-fin tube on heat transfer and resistance characteristics, ten different bundle were studied in this paper. The transverse pitch longitudinal bundles, fin spacing height characteristics obtained, corresponding correlations proposed. results showed that convection coefficient flow increased with tube. decreased, increased. change had little effect performance bundles.

Abstract The supercritical carbon dioxide (S-CO 2 ) Brayton cycle has the advantages of high efficiency, compactness and simplicity. It is expected to become main technical route for future advanced ship nuclear power platform. printed circuit heat exchanger (PCHE) with ultra-high pressure, ultra-compact efficiency typical characteristics ideal configuration S-CO generation system recuperator. PCHE numerical analysis model constructed thermal stress field core structure analyzed by...

Steam generator (SG) is one of the key equipment nuclear power units. Because large range its loads changing, water level control SG effectively an essential secure guarantee plants. a complex system, besides imbalance and non-minimum phase characteristic, it also has properties nonlinearity, time-varying with small stability margin. There are many difficulties in SG. Of which false varying parameters most severe problems. In this paper, first features principle U-tube steam (UTSG)...

In nuclear power plant system, pump is the key equipment to maintain flow of primary loop coolant and secondary heat transfer fluid. The main feed water are in long-term operation status. Bearings components ensure stable pump, which could be damaged abnormal conditions. Once failure occurred bearings, pumps would exhibit periodic vibration, might cause pulsations fluid; gradually, these situations reduce control accuracy stability pump. Therefore, detection diagnosis bearings significant...

As one of the most important subsystem types in nuclear power system, closed-loop cooling system is used for heat transfer system. The control quality its operating temperature safe operation entire This paper proposes an intelligent method based on deep reinforcement learning (DRL). First, simulator built and expanded to provide experimental platform implementation DRL. Secondly, a DRL interaction designed prior knowledge such as thermal characteristics targets. Finally, improved Q-network...

Numerous T-junction circular channels are used in the pipeline system of marine dynamic platforms. Unlike terrestrial conditions, fluid inside experiences additional inertial forces due to rolling motion, leading complex and variable mixing characteristics within pipes. The flow pressure drop were investigated pipe under motion including average value, fluctuation instantaneous value. working is considered as de-ionized water. inlet Reynolds number main ranges from 2110 25 320, rate ratio 1...

Abstract The microchannel flow boiling cooling technology has great potential for application in electronic devices under high heat flux conditions. Saturated microchannels with V-shaped grooved pin fins were simulated using the volume of fluid (VOF) model. working coolant is Novec649. depth-to-width ratio β a single groove set as 0, 1, and 2, respectively. results show that increase β, maximal average temperature heated walls decrease, at q = 100, 300, 500 kW·m-2 2 declined 1.49, 5.29K,...

Abstract Due to its advantages like zero carbon dioxide emissions, high power density, and long life cycle, devices show great application prospects in civil cargo ships icebreakers. The equipment composition structure configuration of plants are complex, with harsh operating conditions, which will yield increased failure rates serious security threats. Given that the relative importance relying on precise data, an intelligent assessment method effects based fuzzy logic is proposed. Marine...

Flue gas after wet desulfurization contains a large quantity of water vapor, as well small amount fine particulate matter, acid and other pollutants. Direct emissions will cause haze environmental pollution. condenser can effectively recover latent heat vaporization remove these However, the traditional flue has disadvantages such volume, low exchange efficiency easy blockage. To overcome problems, new type narrow gap exchanger, which is to detach clean, proposed. Then, condensation...