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Experimental study on film combustion formed by spirally fluted horizontal tube

MEI Ning, ZHANG Bin, ZHAO Jian, ZHANG Ming

《能源前沿（英文）》 2008年 第2卷 第1期   页码 54-58 doi: 10.1007/s11708-008-0023-4

摘要： Falling fuel film on the spirally fluted surface of a horizontal tube can provide rapid fuel evaporation and homogeneous mixture formation. This fuel film combustion could be applied in a micro-combustion system even without a fuel pump. A test bed was established and experimental comparisons were made between the prototype and a transferred cup atomizer micro-combustor. The theoretical and experimental results show that film combustion has a higher combustion efficiency, a lower pollutant emission and a better working performance.

关键词： homogeneous     transferred     evaporation     micro-combustion     efficiency    

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Experimental study on combined buoyant-thermocapillary flow along with rising liquid film on the surface of a horizontalmetallic mesh tube

Manuel J. GOMES, Ning MEI

《能源前沿（英文）》 2020年 第14卷 第1期   页码 114-126 doi: 10.1007/s11708-017-0483-5

摘要： Temperature distribution and variation with time has been considered in the analysis of the influences of the initial level of immersion of a horizontal metallic mesh tube in the liquid on combined buoyant and thermo-capillary flow. The combined flow occurs along with the rising liquid film flow on the surface of a horizontal metallic mesh tube. Three different levels of immersion of the metallic mesh tube in the liquid have been tested. Experiments of 60 min in duration have been performed using a heating metallic tube with a diameter of 25 mm and a length of 110 mm, sealed outside with a metallic mesh of 178 mm by 178 mm, and distilled water. These reveal two distinct flow patterns. Thermocouples and infrared thermal imager are utilized to measure the temperature. The level of the liquid free surface relative to the lower edge of the tube is measured as angle . The results show that for a smaller angle, or a low level of immersion, with a relatively low heating power, it is possible to near fully combine the upwards buoyant flow with the rising liquid film flow. In this case, the liquid is heated only in the vicinity of the tube, while the liquid away from the flow region experiences small changes in temperature and the system approaches steady conditions. For larger angles, or higher levels of immersion, a different flow pattern is noticed on the liquid free surface and identified as the thermo-capillary (Marangoni) flow. The rising liquid film is also present. The higher levels of immersion cause a high temperature gradient in the liquid free surface region and promote thermal stratification; therefore the system could not approach steady conditions.

关键词： rising liquid film     combined flow     thermo-capillary flow     buoyant flow     metallic mesh tube     horizontal tube    

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Numerical simulation of liquid falling film on horizontal circular tubes

Fengdan SUN, Songlin XU, Yongchuan GAO

《化学科学与工程前沿（英文）》 2012年 第6卷 第3期   页码 322-328 doi: 10.1007/s11705-012-1296-z

摘要： The objective of this study is to investigate numerically the flow characteristics of falling film on horizontal circular tubes. Numerical simulations are performed using FLUENT for 2D configurations with one and two cylinders. The volume of fluid method is used to track the motion of liquid falling film and the gas-liquid interface. The effect of flow characteristics on heat and transfer coefficient may be remarkable, although it has been neglected in previous studies. The velocity distribution and the film thickness characteristics on the top tube, some special flow characteristics on the bottom tube, intertube flow modes and effect of liquid feeder height on flow characteristics have been studied. Our simulations indicate that 1) the velocity distributions of the upper and lower parts of the tube are not strictly symmetric and non-uniform, 2) the film thickness depends on flow rate and angular distributions, 3) the flow characteristics of the top tube are different from those of the bottom tube, 4) three principal and two intermediate transition modes are distinguished, and 5) the liquid feed height plays an important role on the formation of falling film. The numerical results are in a good agreement with the theoretical values by the Nusselt model and the reported results.

关键词： falling film     horizontal tube     flow characteristics     film thickness     liquid feeder height    

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Study of two-phase flow regime identification in horizontal tube bundles under vertical upward cross-flow

HUANG Xinghua, WANG Li, JIA Feng

《能源前沿（英文）》 2008年 第2卷 第3期   页码 333-338 doi: 10.1007/s11708-008-0043-0

摘要： A wavelet-transform based approach for flow regime identification in horizontal tube bundles under vertical upward cross-flow condition was presented. Tests on two-phase flow pattern of R134a were conducted under low mass velocity and flow boiling conditions over ranges of mass flux 4–25 kg/ms, vapor quality 0.02–0.90. Time series of differential pressure fluctuations were measured and analyzed with discrete wavelet transform. Different time-scale characteristics in bubbly flow, churn flow and annular flow were analyzed. The wavelet energy distributions over scales were found to be appropriate for flow regime identification. Based on the wavelet energy distribution over characteristic scales, a criterion of flow regime identification was proposed. The comparison with experiment results show that it is feasible to use the discrete wavelet transform as the tool of flow regime identification in horizontal tube bundles under vertical upward cross-flow condition.

关键词： two-phase     discrete     appropriate     wavelet-transform     criterion    

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Natural convection heat transfer of water in a horizontal circular gap

SU Guanghui, WU Yingwei, Kenichiro Sugiyama

《能源前沿（英文）》 2007年 第1卷 第2期   页码 167-173 doi: 10.1007/s11708-007-0021-y

摘要： An experimental study on the natural convection heat transfer on a horizontal downward facing heated surface in a water gap was carried out under atmospheric pressure conditions. A total of 700 experimental data points were correlated using Rayleigh versus Nusselt number in various forms, based on different independent variables. The effects of different characteristic lengths and film temperatures were discussed. The results show that the buoyancy force acts as a resistance force for natural convection heat transfer on a downward facing horizontal heated surface in a confined space. For the estimation of the natural convection heat transfer under the present conditions, empirical correlations in which Nusselt number is expressed as a function of the Rayleigh number, or both Rayleigh and Prandtl numbers, may be used. When it is accurately predicted, the Nusselt number is expressed as a function of the Rayleigh and Prandtl numbers, as well as the gap width-to-heated surface diameter ratio; and uses the temperature difference between the heated surface and the ambient fluid in the definition of Rayleigh number. The characteristic length is the gap size and the film temperature is the average fluid temperature.

关键词： function     diameter     different independent     different characteristic     horizontal downward    

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Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 606-624 doi: 10.1007/s11709-023-0925-6

摘要： A novel cambered surface steel tube damper (CSTD) with a cambered surface steel tube and two concave connecting plates is proposed herein. The steel tube is the main energy dissipation component and comprises a weakened segment in the middle, a transition segment, and an embedded segment. It is believed that during an earthquake, the middle weakened segment of the CSTD will be damaged, whereas the reliability of the end connection is ensured. Theoretical and experimental studies are conducted to verify the effectiveness of the proposed CSTD. Formulas for the initial stiffness and yield force of the CSTD are proposed. Subsequently, two CSTD specimens with different steel tube thicknesses are fabricated and tested under cyclic quasi-static loads. The result shows that the CSTD yields a stable hysteretic response and affords excellent energy dissipation. A parametric study is conducted to investigate the effects of the steel tube height, diameter, and thickness on the seismic performance of the CSTD. Compared with equal-stiffness design steel tube dampers, the CSTD exhibits better energy dissipation performance, more stable hysteretic response, and better uniformity in plastic deformation distributions.

关键词： cambered surface steel tube damper     energy dissipation capacity     finite element model     hysteretic performance     parametric study    

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Numerical analysis of bearing behaviors of single batter piles under horizontal loads in various directions

《结构与土木工程前沿（英文）》 2023年 第17卷 第2期   页码 224-237 doi: 10.1007/s11709-022-0914-1

摘要： The horizontal bearing behavior of a single batter pile (SBP) is vital to its application in practical engineering; however, the horizontal responses of SBPs change with the directions of horizontal loads, and this phenomenon is rarely investigated. Therefore, the directional differences in the horizontal bearing behaviors of SBPs are investigated in this study. Four model tests are conducted to preliminarily examine the effects of the skew angle of horizontal loads on the horizontal bearing capacities and distributions of the bending moments of the SBPs. Subsequently, the differences in the responses of the SBPs under horizontal loads in various directions at full scale are analyzed comprehensively via finite-element (FE) analysis. The effects of the skew angle on SBP-soil interaction are discussed. Moreover, an empirical design method is proposed based on the FE analysis results to predict the bearing ratios of SBPs in medium-dense and dense sand while considering the effects of the skew angle, batter angle, and pile diameter. The method is confirmed to be effective, as confirmed by the close agreement between the predicting results with the model test (reported in this study) and centrifuge model test results (reported in the literature).

关键词： single batter pile     skew horizontal load     model test     finite-element analysis     empirical design method    

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Experimental study on shear behavior of reinforced concrete beams with web horizontal reinforcement

Dong XU,Yu ZHAO,Chao LIU

《结构与土木工程前沿（英文）》 2014年 第8卷 第4期   页码 325-336 doi: 10.1007/s11709-014-0080-1

摘要： In determining the shear capacity of reinforced concrete beams, current codes do not provide any calculation method to evaluate the influence of web horizontal reinforcement, although they exist as structural reinforcements (or skin reinforcement). The present paper comprises results of 11 reinforced concrete beams in an effort to investigate the influence of web horizontal reinforcement on the shear behavior of reinforced concrete beams. The primary design variables are the shear-span-depth ratio, different reinforcement ratio of stirrups and web horizontal reinforcement. Influence of web horizontal reinforcement on crack patterns and failure mode was studied. It was found that web horizontal reinforcement can increase the shear capacity of the beams and restrain growth of inclined cracks effectively. Test results are very valuable, as very few references of shear tests can be found focusing on the effect of web horizontal reinforcement on the shear capacity of the beams.

关键词： reinforced concrete beam     shear strength     web horizontal reinforcement     experiments    

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Optimization model for rotor blades of horizontal axis wind turbines

LIU Xiong, CHEN Yan, YE Zhiquan

《机械工程前沿（英文）》 2007年 第2卷 第4期   页码 483-488 doi: 10.1007/s11465-007-0084-9

摘要： This paper presents an optimization model for rotor blades of horizontal axis wind turbines. The model refers to the wind speed distribution function on the specific wind site, with an objective to satisfy the maximum annual energy output. To speed up the search process and guarantee a global optimal result, the extended compact genetic algorithm (ECGA) is used to carry out the search process. Compared with the simple genetic algorithm, ECGA runs much faster and can get more accurate results with a much smaller population size and fewer function evaluations. Using the developed optimization program, blades of a 1.3 MW stall-regulated wind turbine are designed. Compared with the existing blades, the designed blades have obviously better aerodynamic performance.

关键词： population     extended     algorithm     developed optimization     accurate    

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Transversal tube pitch effects on local heat transfer characteristics of the flat tube bank fin mounted

Liangbi WANG, Zhimin LIN, Kangjie SUN, Yuanxin DONG, Song LIU, Yongheng ZHANG,

《能源前沿（英文）》 2010年 第4卷 第3期   页码 333-345 doi: 10.1007/s11708-009-0061-6

摘要： The tube bank fin is commonly used to increase the area of the heat transfer surface with a small heat transfer coefficient of a heat exchanger. If vortex generators (VGs) are punched on the fin surface, the heat transfer performance of the fin can be improved. This paper focused on the effect of transversal tube pitch on the local heat transfer performance of the three-row flat tube bank fin mounted with VGs. On the fin surface, constructing the flow channel but without mounted VGs, the transversal tube pitch was greater, and the span averaged Nusselt number downstream was larger because fewer interactions of vortices would be generated from different VGs located upstream. When the area goodness factor was used as the criteria on the condition of one tube unit of heat exchanger for commonly used fin materials and fin thickness, the transversal tube pitch has considerable effect on the heat transfer enhancement of VGs. Large transversal tube pitch is more sensitive to fin material than to fin thickness.

关键词： heat transfer enhancement     vortex generator     finned flat tube bank     heat exchanger    

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Energy distribution between liquid hydrogen and liquid oxygen temperatures in a Stirling/pulse tube refrigerator

《能源前沿（英文）》 2023年 第17卷 第4期   页码 516-526 doi: 10.1007/s11708-022-0844-6

摘要： A two-stage gas-coupled Stirling/pulse tube refrigerator (SPR), whose first and second stages respectively involve Stirling and pulse tube refrigeration cycles, is a very promising spaceborne refrigerator. The SPR has many advantages, such as a compact structure, high reliability, and high performance, and is expected to become an essential refrigerator for space applications. In research regarding gas-coupled regenerative refrigerator, the energy flow distribution between the two stages, and optimal phase difference between the pressure wave and volume flow, are two critical parameters that could widely influence refrigerator performance. The effects of displacer displacement on the pressure wave, phase difference, acoustic power distribution, and inter-stage cooling capacity shift of the SPR have been investigated experimentally. Notably, to obtain the maximum first-stage cooling capacity, an inflection point in displacement exists. When the displacer displacement is larger than the inflection point, the cooling capacity could be distributed between the first and second stages. In the present study, an SPR was designed and manufactured to work between the liquid hydrogen and liquid oxygen temperatures, which can be used to cool small-scale zero boil-off systems and space detectors. Under appropriate displacer displacement, the SPR can reach a no-load cooling temperature of 15.4 K and obtain 2.6 W cooling capacity at 70 K plus 0.1 W cooling capacity at 20 K with 160 W compressor input electric power.

关键词： Stirling/pulse tube refrigerator     displacer displacement     space application     phase shift     energy distribution    

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Numerical simulation on flow of ice slurry in horizontal straight tube

Shengchun LIU,Ming SONG,Ling HAO,Pengxiao WANG

《能源前沿（英文）》 2021年 第15卷 第1期   页码 201-207 doi: 10.1007/s11708-017-0451-0

摘要： Numerical simulation on flow of ice slurry in horizontal straight tubes was conducted in this paper to improve its transportation characteristics and application. This paper determined the influence of the diameter and length of tubes, the ice packing factors (IPF) and the flow velocity of ice slurry on pressure loss by using numerical simulation, based on two-phase flow and the granular dynamic theory. Furthermore, it was found that the deviation between the simulation results and experimental data could be reduced from 20% to 5% by adjusting the viscosity which was reflected by velocity. This confirmed the reliability of the simulation model. Thus, two mathematical correlations between viscosity and flow velocity were developed eventually. It could also be concluded that future rheological model of ice slurry should be considered in three sections clarified by the flow velocity, which determined the fundamental difference from single-phase fluid.

关键词： ice slurry     horizontal tubes     numerical simulation     pressure drop     viscosity model    

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Genetic evidence in planar cell polarity signaling pathway in human neural tube defects

null

《医学前沿（英文）》 2014年 第8卷 第1期   页码 68-78 doi: 10.1007/s11684-014-0308-4

摘要：

Neural tube defects (NTDs) are a group of birth anomalies having a profound physical, emotional, and financial effects on families and communities. Their etiology is complex, involving environmental and genetic factors that interact to modulate the incidence and severity of the developing phenotype. The planar cell polarity (PCP) pathway controls the process of convergent extension (CE) during gastrulation and neural tube closure and has been implicated in the pathogenesis of NTDs in animal models and human cohorts. This review summarizes the cumulative results of recent studies on PCP signaling pathway and human NTDs. These results demonstrate that PCP gene alterations contribute to the etiology of human NTDs.

关键词： planar cell polarity     neural tube defects     rare mutations    

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β-粒子在穿越铜狭缝中的横向台阶分布

朱永强,郝建宇

《中国工程科学》 2008年 第10卷 第8期   页码 81-86

摘要：

文章研究了电子高速运动时所产生的横向振动。实验方法是利用半圆聚焦β-谱仪上90Sr源β-粒子在不同磁场下对于相同弯曲半径下β-粒子具有不同的能量和动量的特性，研究这些β-粒子在通过不同宽度的铜狭缝（厚8 mm）时的粒子数n和铜狭缝宽度δ的函数关系，发现不管β-粒子具有什么能量和动量，都具有横向运动的趋势和在铜狭缝中出现了台阶分布。其原因可能是β-粒子本身具有横向振幅A和周围真空起伏能量的相互作用。

关键词： β-粒子的横向振动     铜狭缝宽度     横向台阶分布    

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Theoretical prediction and validation of global horizontal solar irradiance for a tropical climate in

Sivasankari SUNDARAM,Jakka SARAT CHANDRA BABU

《能源前沿（英文）》 2015年 第9卷 第3期   页码 311-321 doi: 10.1007/s11708-015-0369-3

摘要： This paper aims to propose monthly models responsible for the theoretical evaluation of the global horizontal irradiance of a tropical region in India which is Sivagangai situated in Tamilnadu. The actual measured global horizontal irradiance hails from a 5 MW solar power plant station located at Sivagangai in Tamilnadu. The data were monitored from May 2011 to April 2013. The theoretical assessment was conducted differently by employing a programming platform called Microsoft Visual Basic 2010 Express. A graphical user interface was created using Visual Basic 2010 Express, which provided the evaluation of empirical parameters for model formulation such as daily sunshine duration ( ), maximum possible sunshine hour duration ( ), extra terrestrial horizontal global irradiance ( ) and extra terrestrial direct normal irradiance ( ). The proposed regression models were validated by the significance of statistical indicators such as mean bias error, root mean square error and mean percentage error from the predicted and the actual values for the region considered. Comparison was made between the proposed monthly models and the existing normalized models for global horizontal irradiance evaluation.

关键词： global horizontal irradiance (GHI)     mean bias error     root mean square error     mean percentage error     coefficient of regression     Visual Basic 2010 Express    

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标题 作者 时间 类型 操作

Experimental study on film combustion formed by spirally fluted horizontal tube

MEI Ning, ZHANG Bin, ZHAO Jian, ZHANG Ming

期刊论文

Experimental study on combined buoyant-thermocapillary flow along with rising liquid film on the surface of a horizontalmetallic mesh tube

Manuel J. GOMES, Ning MEI

期刊论文

Numerical simulation of liquid falling film on horizontal circular tubes

Fengdan SUN, Songlin XU, Yongchuan GAO

期刊论文

Study of two-phase flow regime identification in horizontal tube bundles under vertical upward cross-flow

HUANG Xinghua, WANG Li, JIA Feng

期刊论文

Natural convection heat transfer of water in a horizontal circular gap

SU Guanghui, WU Yingwei, Kenichiro Sugiyama

期刊论文

Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

期刊论文

Numerical analysis of bearing behaviors of single batter piles under horizontal loads in various directions

期刊论文

Experimental study on shear behavior of reinforced concrete beams with web horizontal reinforcement

Dong XU,Yu ZHAO,Chao LIU

期刊论文

Optimization model for rotor blades of horizontal axis wind turbines

LIU Xiong, CHEN Yan, YE Zhiquan

期刊论文

Transversal tube pitch effects on local heat transfer characteristics of the flat tube bank fin mounted

Liangbi WANG, Zhimin LIN, Kangjie SUN, Yuanxin DONG, Song LIU, Yongheng ZHANG,

期刊论文

Energy distribution between liquid hydrogen and liquid oxygen temperatures in a Stirling/pulse tube refrigerator

期刊论文

Numerical simulation on flow of ice slurry in horizontal straight tube

Shengchun LIU,Ming SONG,Ling HAO,Pengxiao WANG

期刊论文

Genetic evidence in planar cell polarity signaling pathway in human neural tube defects

null

期刊论文

β-粒子在穿越铜狭缝中的横向台阶分布

朱永强,郝建宇

期刊论文

Theoretical prediction and validation of global horizontal solar irradiance for a tropical climate in

Sivasankari SUNDARAM,Jakka SARAT CHANDRA BABU

期刊论文