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Tingkuan Chen - One of the best experts on this subject based on the ideXlab platform.
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an investigation on heat transfer characteristics of different Pressure steam water in vertical upward tube
Nuclear Engineering and Design, 2009Co-Authors: Qincheng Bi, Dong Yang, Tingkuan ChenAbstract:Abstract Within the range of Pressure from 9 to 30 MPa, mass velocity from 600 to 1200 kg/(m 2 s), and heat flux at inner wall from 200 to 600 kW/m 2 , experiments have been performed to investigate the heat transfer characteristics of steam-water two-phase flow in vertical upward tube. The outer diameter of the tube is 32 mm, and the wall thickness is 3 mm. Based on results, it was found that Dryout is the main mechanism of the heat transfer deterioration in the sub-critical Pressure Region. Near the critical Pressure, when the heat transfer deterioration occurs, the steam quality of water is lower than that in the sub-critical Pressure Region, so that DNB is the main mechanism in this Pressure Region. At supercritical Pressure, the heat transfer performance in circular channel is improved and enhanced. Heat transfer deterioration phenomenon is observed when the fluid bulk temperature approaches to the pseudo-critical value. Nusselt correlation of the forced-convection heat transfer in supercritical Pressure Region has been provided, which can be used to predict heat transfer coefficient of the vertical upward flow in tube.
R. M. Fristrom - One of the best experts on this subject based on the ideXlab platform.
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Study of the structure of a ten-atmosphere H_2-O_2-Ar flame using molecular-beam inlet mass-spectrometrometric probing
Combustion Explosion and Shock Waves, 1996Co-Authors: A. A. Paletskii, L. V. Kuibida, T. A. Bolshova, O. P. Korobeinichev, R. M. FristromAbstract:The structure of a stabilized flame of an argon-diluted, stoichiometric hydrogen-oxygen-argon mixture at Pressures of 1 and 10 atm was studied experimentally. Concentration profiles of stable species and flame-front temperature were obtained. At p=10 atm, the width of the chemical-reaction zone is 0.7 mm and is weakly dependent on flow rate. Comparison with the available models of hydrogen combustion and the data obtained at p=1 atm indicates that extrapolation of the mechanism and rate constants of chemical reactions from a low-Pressure Region to a higher-Pressure Region is not justified.
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study of the structure of a ten atmosphere h2 o2 ar flame using molecular beam inlet mass spectrometrometric probing
Combustion Explosion and Shock Waves, 1996Co-Authors: A. A. Paletskii, L. V. Kuibida, T. A. Bolshova, O. P. Korobeinichev, R. M. FristromAbstract:The structure of a stabilized flame of an argon-diluted, stoichiometric hydrogen-oxygen-argon mixture at Pressures of 1 and 10 atm was studied experimentally. Concentration profiles of stable species and flame-front temperature were obtained. At p=10 atm, the width of the chemical-reaction zone is 0.7mm and is weakly dependent on flow rate. Comparison with the available models of hydrogen combustion and the data obtained at p=1atm indicates that extrapolation of the mechanism and rate constants of chemical reactions from a low-Pressure Region to a higher-Pressure Region is not justified.
Dong Yang - One of the best experts on this subject based on the ideXlab platform.
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Self-compensating characteristic of steam–water mixture at low mass velocity in vertical upward parallel internally ribbed tubes
Applied Thermal Engineering, 2010Co-Authors: Xiaojing Zhu, Dong Yang, Jianguo WangAbstract:Abstract This paper presents an experimental investigation on Self-Compensating Characteristic (SCC) in vertical upward parallel tubes with low mass velocity of steam–water two-phase mixture. A physical model was built up using parallel internally ribbed tubes. A method called Differential Pressure Substitute was used to measure two-phase flow parameters. The results indicated that the SCC of vertical upward parallel tubes is caused by combined action of frictional Pressure drop and gravitational Pressure drop. The mass velocity in the tube with lower heat flux decreases first, and then increases with an increase in quality. The uneven heat fluxes among tubes are the main reasons that cause mass velocity differentials. Greater uneven heating ratio enhances the SCC in low quality Region and weakens it in high quality Region. The SCC has different variation rules in different Pressure Region. In the sub-critical Pressure Region, rising Pressure weakens the SCC when quality is low and enhances it when quality is high. In near-critical Pressure Region, the mass velocity varies monotonically and slowly with the increase in quality because the difference between water and steam is minor in this Pressure Region. The results provide some instructive advices to improve the design and operation safety of once-through boiler.
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an investigation on heat transfer characteristics of different Pressure steam water in vertical upward tube
Nuclear Engineering and Design, 2009Co-Authors: Qincheng Bi, Dong Yang, Tingkuan ChenAbstract:Abstract Within the range of Pressure from 9 to 30 MPa, mass velocity from 600 to 1200 kg/(m 2 s), and heat flux at inner wall from 200 to 600 kW/m 2 , experiments have been performed to investigate the heat transfer characteristics of steam-water two-phase flow in vertical upward tube. The outer diameter of the tube is 32 mm, and the wall thickness is 3 mm. Based on results, it was found that Dryout is the main mechanism of the heat transfer deterioration in the sub-critical Pressure Region. Near the critical Pressure, when the heat transfer deterioration occurs, the steam quality of water is lower than that in the sub-critical Pressure Region, so that DNB is the main mechanism in this Pressure Region. At supercritical Pressure, the heat transfer performance in circular channel is improved and enhanced. Heat transfer deterioration phenomenon is observed when the fluid bulk temperature approaches to the pseudo-critical value. Nusselt correlation of the forced-convection heat transfer in supercritical Pressure Region has been provided, which can be used to predict heat transfer coefficient of the vertical upward flow in tube.
J. H. Tweed - One of the best experts on this subject based on the ideXlab platform.
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Constitutive model for powders with characterisation of low Pressure Region of yield surface
Powder Metallurgy, 2011Co-Authors: S.a. Rolland, David T. Gethin, Roland W. Lewis, J. H. TweedAbstract:Numerical simulations of manufacturing processes rely on material characterisation. This highlights the need for a close combination of experimental and numerical work to model cold die powder compaction. Based on a previous experimental work by the authors, this document shows how the data collected can be used to formulate a constitutive model reflecting the material behaviour in a broad range of conditions. A plasticity model based on Pressure and deviatoric stress was chosen. Particular attention was given to the definition of the yield properties under low Pressure levels. This choice was motivated by the previous review of experimental techniques for powder characterisation and, in contrast with popular models which focus on the behaviour of the powder in conditions close to idealised frictionless uniaxial compaction, the updated model achieves a very good agreement with out of die tests for two different materials while retaining a single equation formulation for the yield surface.
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Characterisation of powders in low Pressure Region of yield surface
Powder Metallurgy, 2010Co-Authors: S.a. Rolland, David T. Gethin, Roland W. Lewis, J. H. TweedAbstract:AbstractCold die powder compaction can be a challenging manufacturing route for complex components. Setting the filling and pressing tools is a difficult and time consuming operation. Numerical methods can assist process engineers; however, the result can only reflect the reality if the material characteristics are well established mathematically for the simulation systems. The aim of the present work is to review two tests, which are easy to set up, and review them with the aim of establishing whether or not they produce useful and accurate data to establish a mathematical description of the material behaviour. The work draws attention to the limitations within which data from the simple compression test and the Brazilian disc test can be used to establish the behaviour of powders under shear dominated stress and strain conditions. The study is conducted on a ferrous and an alumina powder to highlight differences in behaviour. The present work is followed by a complementary article showing the exploitati...
Li Haochang - One of the best experts on this subject based on the ideXlab platform.
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passenger and freight ultra high speed ship and ultra high speed warship capable of eliminating wave making resistance
2016Co-Authors: Li HaochangAbstract:The invention discloses a passenger and freight ultra-high-speed ship and an ultra-high-speed warship capable of eliminating wave-making resistance. Recent a hundred years, the operation speed of automobiles is increased by more than ten times, the operation speed of trains is increased by more than twenty times, the operation speed of airplanes is increased by more than thirty times, however, only the operation speed of steamships is increased by one time due to the fact that the wave-making resistance is an obstacle which cannot be crossed. By the adoption of the technical scheme, a fairing with the area equivalent to the sectional area of a hull is additionally arranged below a water line of a bow, each of the left side and the right side is provided with multiple propellers, water delivery tunnels are additionally arranged on ship sides on the two sides, water flow is strongly pushed by the propellers to rush to a stern at the high speed from the bow through the water delivery tunnels all the time, an original bow high-Pressure Region is changed into a low-Pressure Region, an original stern low-Pressure Region is changed into a high-Pressure Region, and the wave-making resistance completely disappears; and the economic speed of the steamship speed per hour is 20 km, the medium speed of passenger ship speed per hour is 30 km, the power is enlarged by one time when the speed per hour is only enlarged by 1/2, the power is enlarged by 47 times if the speed per hour is further enlarged by one time and reaches 60 km, and in other words, the power is increased in a cubic manner. By the utilization of the scheme, the power may only need to be enlarged by 10 times, and the unparalleled superiority of the scheme is proved.
