【摘 要】
：
The experimental measurement of supercritical pressure carbon dioxide (sCO2) heat transfer in vertical downward flow was performed in a circular tube with inner diameter of 10 mm.Then,a three-dimensional numerical investigation of sCO2 heat transfer in up
【机 构】
：
Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization,North C
论文部分内容阅读
The experimental measurement of supercritical pressure carbon dioxide (sCO2) heat transfer in vertical downward flow was performed in a circular tube with inner diameter of 10 mm.Then,a three-dimensional numerical investigation of sCO2 heat transfer in upward and downward flows was performed in a vertical heated circular tube.The influence of heat flux,mass flux,and operating pressure on heat transfer under different flow directions were discussed.According to the “pseudo-phase tran-sition” viewpoint to supercritical fluids,the analogy to the subcritical inverted-annular film boiling model,the physical model to sCO2 heat transfer was established,where fluid region at the cross-section of circular tube was divided into gas-like region covering heated wall and core liquid-like phase region.Then,the thermal resistance mechanism which comprehensively reflected the effect of multiple factors including the thickness of the gas-like film or liquid-like region,fluid properties and turbulence on heat diffusion was proposed.Surprisingly,thermal resistance variation in upward flow is well identical with that of wall temperature and heat transfer deterioration is predicted successfully.In addition,compared with thermal resistance in the core liquid-like region,gas-like film formation is determined to be the primary factor affecting heat transfer behavior.Results also show that total thermal resistance in upward flow is always larger than that in downward flow.The investigation can provide valuable guide to design and optimize sCO2 heaters.
其他文献
Developing high sensitive organic semiconductors (OSCs) in organic thin-film transistors (OTFTs) is the key for OTFT based gas sensors.Herein,we report a simple processing route of highly sensitive OSCs for high performance OTFT based nitrogen dioxide (NO
The perfectly matched layer (PML) boundary condition has been proven to be effective for attenuating reflections from model boundaries during wavefield simulation.As such,it has been widely used in time-domain finite-difference wavefield simulations.The c
Electromagnetic induction effect caused by neuron potential can be mimicked using memristor.This paper considers a flux-controlled memristor to imitate the electromagnetic induction effect of adapting feedback synapse and presents a memristive neuron mode
For the detection of shallow underwater targets by the hyperspectrum,the information of the target is carried in the water-leaving radiation.However,the differences between the water-leaving radiation of the underwater target and the ocean background radi
Landslides are recurrent geological phenomena on Earth that cause heavy casualties and property losses annually.In this study,we use the Vp-k stacking and nonlinear waveform inversion methods of high-frequency receiver functions extracted from local earth
Predicting the failure time of unstable slopes is one of the most pivotal issues.In this paper,the inverse square root acceleration(INSRA) method was proposed to estimate the time-of-failure (TOF) of landslides.Four collapsed slopes were presented in the
High-quality graphene is prepared by arc discharge with low cost under hydrogen atmosphere.However,the growth mechanism of graphene synthesis by arc discharge remains unclear.In this paper,the hydrogen-induced marginal growth (HIMG) model is deduced to st
Carbonate reservoirs have complex pore structures,which not only significantly affect the elastic properties and seismic responses of the reservoirs but also affect the accuracy of the prediction of the physical parameters.The existing rock-physics invers
In order to improve the agility and applicability of trajectory planning algorithm for autonomous vehicles,this paper proposes a novel actor-critic based learning method for decision-making and planning in multi-vehicle complex traffic.It is the coupling
This paper solves the robust control problem of robotic manipulator systems with uncertain dynamics by friction compensation approach.A weighting factor is introduced to distinguish the role of friction in control process by comparing the directions of sl