In this paper, the characteristics of effervescent atomization are studied experimentally. A high speed camera was used to record the bubbling process and the change of the flow regime in the mixing chamber. Three typ...
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The reasons of frequent tube burst of the high temperature reheater in a supercritical 600 MW unit were systematically investigated via the examination of macroscopic inspection, chemical composition, mechanical prope...
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ISBN:
(数字)9781728191645
ISBN:
(纸本)9781728191652
The reasons of frequent tube burst of the high temperature reheater in a supercritical 600 MW unit were systematically investigated via the examination of macroscopic inspection, chemical composition, mechanical properties, microstructures, scanning electron microscope and energy disperse spectroscopy detection. It is demonstrated that the tube burst of the high temperature reheater results from not only design factors, but also manufacture quality. Due to the absence of solid solution treatment in spare elbow, the inner dislocations and residual stress increase obviously, which accelerates the precipitation of carbide containing Cr and the formation of Cr depleted zone on grain boundary(GB) subsequently, leading to the decrease of GB corrosion resistance and the final leakage of high temperature reheater tube induced by intergranular corrosion.
The erosion-corrosion behavior poses a significant threat to marine equipment, driven by complex multi-physics processes such as sand movement, surface erosion, electrochemical reactions, and corrosive ion transport. ...
The erosion-corrosion behavior poses a significant threat to marine equipment, driven by complex multi-physics processes such as sand movement, surface erosion, electrochemical reactions, and corrosive ion transport. Aiming at the widely used rotating liquid-solid two-phase flow system in a marine environment, this study investigates the role of flow velocity in the erosion-corrosion behavior of Ni 2 FeCrMo 0.2 alloy. The coupling analysis of multi-component weight loss, electrochemical kinetics, and microstructure characterization clarifies the interactions between fluid flow, sand migration, ion transfer, and damage morphology, revealing the synergistic erosion-corrosion mechanism. The results show that the erosion-corrosion mechanism transfers with flow velocity. At low velocities, the erosion effect on the harder metal matrix is weak due to insufficient kinetic energy of the sand particles. However, the sand-surface impingement on the softer corrosion products and the mass transfer of corrosive ions lead to erosion-enhanced corrosion, which dominates the material damage process. In contrast, at higher velocities, the impact kinetic energy and frequency of sand particles rise, causing the erosion rate to increase exponentially, which surpasses corrosion, making erosion as the dominant damage mechanism at high velocities. These results highlight the critical role of flow velocity in controlling the erosion-corrosion synergy behavior.
In this study the effect of thermal spray process on wear resistance of NiAl/Cr2C3 thermal spray coating has been investigated. For this purpose the NiAl power mixed with 10 %wt. Cr2C3 powder and milled for 1 hrs at a...
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Based on the GSE software, the simulation model of an ultra-supercritical double-reheat tower boiler was established, and its reliability was checked with design data. Then, the dynamic characteristics of the ultra-su...
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Based on the GSE software, the simulation model of an ultra-supercritical double-reheat tower boiler was established, and its reliability was checked with design data. Then, the dynamic characteristics of the ultra-supercritical double-reheat boiler were studied. Simulation results reveal the response times of different input parameters greatly vary. When stepping disturbances to the feed-coal rate, feed-water rate, and feed-water temperature, the response time under feed-water’s temperature disturbance is the longest, which is about 1, 800 s. When the same input parameter disturbs, the output parameters have the same response tendency with different amplitudes. Moreover, the fiercer the disturbance is, the more greatly the parameter changes.
Swirl vane separator is not only used in SG for separating more than 80% of liquid water from steam-water mixture to feed qualified steam to dryers and turbines, but also applied in the thorium molten salt reactor to ...
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