Required by the supercritical carbon dioxide(s CO_(2))coal-fired power cycle,s CO_(2)entering a boiler has a high temperature and can cause overheating of *** eliminate the pressure drop penalty effect,the s CO_(2)boi...
详细信息
Required by the supercritical carbon dioxide(s CO_(2))coal-fired power cycle,s CO_(2)entering a boiler has a high temperature and can cause overheating of *** eliminate the pressure drop penalty effect,the s CO_(2)boiler consists of several modules,each having different heat flux received from the furnace side(q)and different CO_(2)temperature in the cooling wall tube(T_f).We aim to search for the best matching strategy coupling furnace side and tube side to obtain the lowest temperature of *** theoretically analyzing the wall temperature influenced by q,T_f and a comprehensive thermal resistance C,two matching methods are introduced:the heat flux-temperature matching(HTM)which matches higher q with lower T_f,and the heat flux-heat flux matching(HHM)that matches higher q with higher allowable-heat-flux at the temperature limit of *** is a conventional method but HHM is newly proposed *** show that,if C is identical for different modules,the two methods coincide;otherwise,HHM is *** a s CO_(2)boiler driving 1000 MWe power plant,smaller cooling wall temperatures are obtained by HHM than *** on HHM,the mid-partition wall,heat transfer enhancement,and downward flow are comprehensively used,decreasing the wall temperature significantly.
Supercritical water gasification has been confirmed as an advanced treatment method for organic waste including oily sludge. As a supplement to our previous studies, molecular dynamics (MD) simulations must be impleme...
Supercritical water gasification has been confirmed as an advanced treatment method for organic waste including oily sludge. As a supplement to our previous studies, molecular dynamics (MD) simulations must be implemented to understand the gasification mechanism thoroughly. Five representative model compounds were selected to investigate the gasification mechanism using ReaxFF-MD method. The molecular evolution of five key intermediates in SCWG was simulated and compared at 3500 K. To overcome the gasification challenge of oily sludge, toluene was selected for further investigation due to its prominent proportion and relatively low reactivity. Simulations were systematically discussed under different temperatures (2500–3500 K) to study the product distribution. It was found that the yields of the main products (H 2 , CO and CO 2 ) continuously increased with reaction time and temperature. The yields of C1-C3, C4-C7 and C7+ increased more rapidly at higher temperature, with the yield of short-chain carbonaceous organics (C1-C3) being significantly higher than that of other carbonaceous organics. The decomposition kinetics of toluene in supercritical water were also analyzed, and the apparent activation energy was 235.22 ± 22.66 kJ⋅mol −1 . Furthermore, four main gasification pathways were identified by tracking molecular animations. This study would provide valuable insights into the transformation characteristics of oily sludge.
The accurate prediction of subcooled boiling phenomena in narrow rectangular channels is of great importance for the plate type fuel reactor core safety analysis during some critical scenarios. Serious of experimental...
详细信息
Series of experiments have been performed at different pressures from 12 to 19 MPa, mass velocities from 400 to 1000 kg·m-2· s-1, inner wall heat fluxes from 300 to 500 kW· m-2 and bulk fluid enthalpy f...
详细信息
Helium-xenon Brayton cycle systems have significant potential as the energy conversion system for small-scale reactors in remote land,deep-sea,and space applications due to a range of advantages,including high cycle e...
详细信息
Helium-xenon Brayton cycle systems have significant potential as the energy conversion system for small-scale reactors in remote land,deep-sea,and space applications due to a range of advantages,including high cycle efficiency,compact system structures,and chemical *** objective of this review is to provide a comprehensive understanding of the helium-xenon Brayton cycle system based on the projects and ***,the basic information and development history are introduced,and a series of typical designs are ***,the system configurations,cycle parameter analysis and optimization are ***,the key components are classified,such as turbine,compressor,and heat ***,the dynamic processes and control strategies are introduced in different ***,the deficiency and prospect of current research are *** review covers the representative helium-xenon Brayton cycle systems,which could provide a reference for promoting the development of energy conversion systems.
The gas diffusion layer (GDL) serves as a pivotal component governing heat transfer in proton exchange membrane fuel cells (PEMFCs). Excessive heat accumulation within the catalyst layer may lead to irreversible degra...
The gas diffusion layer (GDL) serves as a pivotal component governing heat transfer in proton exchange membrane fuel cells (PEMFCs). Excessive heat accumulation within the catalyst layer may lead to irreversible degradation of electrochemical activity due to accelerated catalyst sintering and carbon support corrosion. Building upon multi-modal characterization integrating micro-computed tomography (Micro-CT) and scanning electron microscopy (SEM) of GDLs, this investigation systematically deciphers the interdependent relationships between fiber architecture, sphere network topology, and compression-mediated morphological evolution through advanced computational analytics and finite element modeling. The quantified synergy elucidates microstructure-property linkages governing anisotropic thermal and gas transport phenomena. The computational findings reveal pronounced anisotropic thermal conduction characteristics within GDLs, demonstrating significantly inferior thermal transport capabilities in the through-plane (TP) direction compared to the in-plane (IP) direction. Reduced fiber length diminishes multi-directional heat dissipation, whereas GDL thickening enhances multi-directional thermal transport efficiency. Quantitative analysis demonstrates a 23-fold higher susceptibility of effective thermal conductivity (ETC) to compression ratio compared to thickness variation, conclusively establishing microstructural heterogeneity as the primary determinant of anisotropic thermal transport. Spatially resolved thermal flux mapping reveals strong geometric coupling with porosity gradients. These multiscale findings provide new design paradigms for optimizing GDL architectures through targeted manipulation of fiber-sphere coupling mechanics.
Nickel and antimony doped tin dioxide (NATO) coated titanium electrodes are prepared and tested for electrochemical treatment of pentachlorophenol (PCP).The effect of nickel content on the electrochemical activity is ...
详细信息
ISBN:
(纸本)9781612843377
Nickel and antimony doped tin dioxide (NATO) coated titanium electrodes are prepared and tested for electrochemical treatment of pentachlorophenol (PCP).The effect of nickel content on the electrochemical activity is studied using PCP as target organic *** nickel content has an optimized value for the *** NATO is characterized and the relationship between activity and oxygen to tin atomic ratio is discussed.
This paper focuses on the laminar flame instability of three high molecular weight n-alkanes,namely n-hexane,n-octane,and *** experiment was carried out in a constant volume combustion bomb to get the flame *** critic...
详细信息
This paper focuses on the laminar flame instability of three high molecular weight n-alkanes,namely n-hexane,n-octane,and *** experiment was carried out in a constant volume combustion bomb to get the flame *** critical radius under different conditions was extracted using the image processing *** with the existing critical Peclet number theory,the dominant factors of flame instability under current conditions for three n-alkanes can be figured ***,the average cell size(equivalent cell radius,R_(cell))was extracted to provide quantitative analysis of the flame cellular structure,based on the method developed in this *** theoretical R_(cell)were also calculated and compared with the experimental results to validate the proposed method.
The liquid phase turbulent structure of an air-water bubbly horizontal flow in a circular pipe has been investigated experimentally. Three-dimensional measurements were implemented with two "X" type probes o...
详细信息
The liquid phase turbulent structure of an air-water bubbly horizontal flow in a circular pipe has been investigated experimentally. Three-dimensional measurements were implemented with two "X" type probes oriented in different planes, and local liquid-phase velocities and turbulent stresses were simultaneously obtained. Systematic measurements were conducted covering a range of local void fraction from 0 to 11.7%. The important experiment results and parametric trends are summarized and discussed.
暂无评论