期刊文献+
共找到2,956篇文章
< 1 2 148 >
每页显示 20 50 100
Effect of Hole Size on Flow Structure and Mixing Characteristic in a Multi-Hole Baffled Micro Combustor
1
作者 Won Hyun Kim Young Su Park +1 位作者 Seon Myeong Park Tae Seon Park 《Journal of Applied Mathematics and Physics》 2017年第1期7-16,共10页
Flow structure and mixing properties by the baffle shape are numerically studied for a baffled micro combustor. The baffle shape is changed by various fuel and hole sizes. The numerical simulations based on different ... Flow structure and mixing properties by the baffle shape are numerically studied for a baffled micro combustor. The baffle shape is changed by various fuel and hole sizes. The numerical simulations based on different geometric conditions are performed by using the Reynolds Stress Model. The fuel-air mixing is greatly affected by flow recirculations. The centrally located flow recirculation has an important role for the entire mixing performance. The results show that this feature depends on the baffle configurations, and the baffle with small air holes represents efficient characters. 展开更多
关键词 Micro COMBUSTOR baffle Diameter Ratio Flow Recirculation MIXING Secondary FLOWS
下载PDF
Protective effects of baffles with different positions,row spacings,heights on debris flow impact
2
作者 SUN Xinpo CHEN Min +5 位作者 BI Yuzhang ZHENG Lu CHE Chi XU Ao TIAN Zijian JIANG Zheyuan 《Journal of Mountain Science》 SCIE CSCD 2024年第7期2352-2367,共16页
The baffle effectively slowed down debris flow velocity,reduced its kinetic energy,and significantly shortened the distance of debris flow movement.Consequently,they are widely used for protection against natural haza... The baffle effectively slowed down debris flow velocity,reduced its kinetic energy,and significantly shortened the distance of debris flow movement.Consequently,they are widely used for protection against natural hazards such as landslides and mudslides.This study,based on the threedimensional DEM(Discrete Element Method),investigated the impact of different baffle positions on debris flow protection.Debris flow velocity and kinetic energy variations were studied through single-factor experiments.Suitable baffle positions were preliminarily selected by analyzing the influence of the first-row baffle position on the impact force and accumulation mass of debris flow.Subsequently,based on the selected baffle positions and four factors influencing the effectiveness of baffle protection(baffle position(P),baffle height(h),row spacing(S_(r)),and angle of transit area(α)),an orthogonal design was employed to further explore the optimal arrangement of baffles.The research results indicate that the use of a baffle structure could effectively slow down the motion velocity of debris flows and dissipate their energy.When the baffle is placed in the transit area,the impact force on the first-row baffle is greater than that when the baffle is placed in the deposition area.Similarly,when the baffle is placed in the transit area,the obstruction effect on debris flow mass is also greater than that when the baffle is placed in the deposition area.Through orthogonal experimental range analysis,when the impact on the first row of baffles is used as the evaluation criterion,the importance of each influencing factor is ranked asα>P>S_(r)>h.When the mass of debris flow behind the baffle is regarded as the evaluation criterion,the rank is changed to P>α>S_(r)>h.The experimental simulation results show that the optimal baffle arrangement is:P_(5),S_(r)=16,α=35°,h=9. 展开更多
关键词 Debris flow baffle Protective effect Discrete element
下载PDF
Wetting front migration model of ion-adsorption rare earth during the multi-hole unsaturated liquid injection
3
作者 Yu Wang Xiaojun Wang +8 位作者 Yuchen Qiu Hao Wang Gang Li Kaijian Hu Wen Zhong Zhongqun Guo Bing Li Chunlei Zhang Guangxiang Ye 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期483-496,共14页
In the process of ion-adsorption rare earth ore leaching,the migration characteristics of the wetting front in multi-hole injection holes and the influence of wetting front intersection effect on the migration distanc... In the process of ion-adsorption rare earth ore leaching,the migration characteristics of the wetting front in multi-hole injection holes and the influence of wetting front intersection effect on the migration distance of wetting fronts are still unclear.Besides,wetting front migration distance and leaching time are usually required to optimize the leaching process.In this study,wetting front migration tests of ionadsorption rare earth ores during the multi-hole fluid injection(the spacing between injection holes was 10 cm,12 cm and 14 cm)and single-hole fluid injection were completed under the constant water head height.At the pre-intersection stage,the wetting front migration laws of ion-adsorption rare earth ores during the multi-hole fluid injection and single-hole fluid injection were identical.At the postintersection stage,the intersection accelerated the wetting front migration.By using the Darcy’s law,the intersection effect of wetting fronts during the multi-hole liquid injection was transformed into the water head height directly above the intersection.Finally,based on the Green-Ampt model,a wetting front migration model of ion-adsorption rare earth ores during the multi-hole unsaturated liquid injection was established.Error analysis results showed that the proposed model can accurately simulate the infiltration process under experimental conditions.The research results enrich the infiltration law and theory of ion-adsorption rare earth ores during the multi-hole liquid injection,and this study provides a scientific basis for optimizing the liquid injection well pattern parameters of ion-adsorption rare earth in situ leaching in the future. 展开更多
关键词 Ion-adsorption rare earth ore multi-hole unsaturated liquid injection In situ leaching Intersection effect Calculation model
下载PDF
Effects of baffle position in serpentine flow channel on the performance of proton exchange membrane fuel cells
4
作者 Guodong Xia Xiaoya Zhang Dandan Ma 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第5期250-262,共13页
This study used a three-dimensional numerical model of a proton exchange membrane fuel cell with five types of channels:a smooth channel(Case 1);eight rectangular baffles were arranged in the upstream(Case 2),midstrea... This study used a three-dimensional numerical model of a proton exchange membrane fuel cell with five types of channels:a smooth channel(Case 1);eight rectangular baffles were arranged in the upstream(Case 2),midstream(Case 3),downstream(Case 4),and the entire cathode flow channel(Case 5)to study the effects of baffle position on mass transport,power density,net power,etc.Moreover,the effects of back pressure and humidity on the voltage were investigated.Results showed that compared to smooth channels,the oxygen and water transport facilitation at the diffusion layer-channel interface were added 11.53%-20.60%and 7.81%-9.80%at 1.68 A·cm^(-2)by adding baffles.The closer the baffles were to upstream,the higher the total oxygen flux,but the lower the flux uniformity the worse the water removal.The oxygen flux of upstream baffles was 8.14%higher than that of downstream baffles,but oxygen flux uniformity decreased by 18.96%at 1.68 A·cm^(-2).The order of water removal and voltage improvement was Case 4>Case 5>Case 3>Case 2>Case 1.Net power of Case 4 was 9.87%higher than that of the smooth channel.To the Case 4,when the cell worked under low back pressure or high humidity,the voltage increments were higher.The potential increment for the back pressure of 0 atm was 0.9%higher than that of 2 atm(1 atm=101.325 kPa).The potential increment for the humidity of 100%was 7.89%higher than that of 50%. 展开更多
关键词 Proton exchange membrane fuel cell baffle position Mass transfer Net power UNIFORMITY Voltage increment
下载PDF
Dynamic Response of A Group of Cylindrical Storage Tanks with Baffles Considering the Effect of Soil Foundation
5
作者 SUN Ying WANG Jia-dong +3 位作者 HUO Rui-li ZHOU Ding GU Zhen-yuan QIAN Wang-ping 《China Ocean Engineering》 SCIE EI CSCD 2024年第1期129-143,共15页
The sloshing in a group of rigid cylindrical tanks with baffles and on soil foundation under horizontal excitation is studied analytically.The solutions for the velocity potential are derived out by the liquid subdoma... The sloshing in a group of rigid cylindrical tanks with baffles and on soil foundation under horizontal excitation is studied analytically.The solutions for the velocity potential are derived out by the liquid subdomain method.Equivalent models with mass-spring oscillators are established to replace continuous fluid.Combined with the least square technique,Chebyshev polynomials are employed to fit horizontal,rocking and horizontal-rocking coupling impedances of soil,respectively.A lumped parameter model for impedance is presented to describe the effects of soil on tank structures.A mechanical model for the soil-foundation-tank-liquid-baffle system with small amount of calculation and high accuracy is proposed using the substructure technique.The analytical solutions are in comparison with data from reported literature and numerical codes to validate the effectiveness and correctness of the model.Detailed dynamic properties and seismic responses of the soil-tank system are given for the baffle number,size and location as well as soil parameter. 展开更多
关键词 cylindrical tanks multiple annular baffles equivalent analytical model soil−structure interaction subdomain method dynamic response
下载PDF
Numerical Examination of a Cavity Containing Nanofluid with an Upper Oscillating Wall and Baffle
6
作者 Kadhum Audaa Jehhef Ali J.Ali +1 位作者 Salah H.Abid Aun Akram H.Abed 《Frontiers in Heat and Mass Transfer》 EI 2024年第2期557-581,共25页
The cavity with lid-driven is greatly used in mixing,coating,and drying applications and is a substantial issue in the study of thermal performance rate and fluid field.A numerical approach is presented to study the t... The cavity with lid-driven is greatly used in mixing,coating,and drying applications and is a substantial issue in the study of thermal performance rate and fluid field.A numerical approach is presented to study the thermal distribution and passage of fluid in a lid-driven cavity with an upper oscillating surface and an attached baffle.The walls of a cavity at the left and right were maintained at 350 and 293 K,respectively.The upper oscillating surface was equipped with a variable height to baffle to increase the convection of the three kinds of TiO_(2),Al_(2)O_(3),andCuO nanofluids with various of 0.4,0.8,and 0.4,0.8,and 1.2 vol.%in volume fractions.It was found that using a baffle attached to the oscillating upper surface of the cavity will lead to improving the distribution of vorticity in the cavity and increase the stream in the cavity.Also,increasing the baffle height,oscillating velocity,and volume fraction of nanoparticles contributes to enhancing the Nusselt number values by 50%for increasing baffle height from h∗=0.1 to 0.1.Also,the Nu improved by 20%for increasing oscillating velocity from w=05 to 20 rad/s and by 12%for using Al_(2)O_(3)nanofluid instead of TiO3 atϕ=0.8 vol.%. 展开更多
关键词 Oscillating wall square lid-driven nanofluids attached baffle
下载PDF
The Effects of Fluid Sloshing on Different Baffle Configurations in Storage Tanks Transported on Trucks during an Emergency Braking
7
作者 Che Martin Ayiehfor 《Open Journal of Fluid Dynamics》 2024年第1期24-63,共40页
Different Baffle designs usable in cylindrical and elliptical storage tanks carried by trucks often used for transporting inflammable liquid materials in Cameroon are investigated to evaluate their safest fluid sloshi... Different Baffle designs usable in cylindrical and elliptical storage tanks carried by trucks often used for transporting inflammable liquid materials in Cameroon are investigated to evaluate their safest fluid sloshing damping response during emergency braking where the magnitude of sloshing waves are the greatest. The uncontrolled fluid sloshing creates thrust on the walls of the tanks usually felt externally on the truck carrying the tank and capable of hindering driver’s effort to maintain steer ability and improve on safety during critical braking moments. The study first passes through COMSOL, to expose the safest margin of each Baffle type at instantaneous fluid pressure wave propagation initiated at a single phase to reflect sloshing in the storage tank during an emergency braking by the truck carrying the tank. The vivid results can be seen in the domain of Acoustic Iso-surface Pressure response;but also acoustic Pressure and Sound pressure response are seen automatically. Secondly, through an experimental finding in which fluid is forced to pass through each Baffle and the resistance to fluid flow is a measured as it’s the Baffle’s damping ability. Either, the fluid is lost through the Baffle and by determination of the surface load exerted on each Baffle due to the reaction of the residual fluid acting on the surface of each Baffle after some of it is Lost, the individual sloshing damping abilities are exposed. By comparing the Experimental outcome with the computational response obtained, an ideal Baffle design is proposed for cylindrical and elliptical tanks and considered to respond to abrupt braking more effciently. The application of the Baffle designs with an average multiple holes rather than the usual face centered proved to be more effcient in fluid sloshing as they provide a more uniformly distributed damping pressure during fluid sloshing in the tank thereby reducing the magnitude of forward thrust that can be created by the conventional Baffle type during emergency braking hence contributing to improving safety. Mindful of the human, material and environmental damages that an accident involving mobile petroleum storage tanks can course, this study is therefore of great significance for design optimization by petroleum storage tank manufacturing companies in Cameroon. 展开更多
关键词 baffles LOSS PRESSURE Sloshing and Iso-Surface
下载PDF
Reduced power consumption in stirred vessel with high solid loading by equipping punched baffles 被引量:3
8
作者 Xia Xiong Zuohua Liu +3 位作者 Changyuan Tao Yundong Wang Fangqin Cheng Hong Li 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第4期203-214,共12页
Solid-liquid suspension in stirred tank is a common operation in the chemical industry. The power consumption, flow pattern and flow field instability of three systems named as unbaffled stirred tank, traditional baff... Solid-liquid suspension in stirred tank is a common operation in the chemical industry. The power consumption, flow pattern and flow field instability of three systems named as unbaffled stirred tank, traditional baffled stirred tank and punched baffled stirred tank(Pun-BST) were studied by using the computational fluid dynamic analysis. Results showed that perforating holes in the baffles could reduce power consumption of mixing. Meanwhile, the punched baffle system could maintain the solids in suspension as traditional baffle system. The results also showed that the baffles could increase the “effective flow” of stirred tank even though the whole velocity of the vessel is lower than un-baffled vessel. In addition, both the solid-liquid suspension and “effective flow” were related to instability of the flow field.Perfect solid-liquid suspension results always along with obvious instability of the flow field. But, the strengthening effect of punched baffle on flow field instability mainly happened in the near-wall area.It's because the collision and aggregation among sub-streams induced by holes intensified the unstable fluid flow. On the whole, the Pun-BST system provided much better mixing characteristics and recommended to apply in the industrial process. 展开更多
关键词 Solid-liquid suspension Punched baffle Energy conservation Flow field instability Effective fluxion
下载PDF
Numerical Investigations of Laminar Air Flow and Heat Transfer Characteristics in a Square Channel Inserted with Discrete X-V Baffles (XVB)
9
作者 Amnart Boonloi Withada Jedsadaratanachai 《Frontiers in Heat and Mass Transfer》 EI 2023年第1期317-336,共20页
Thermal performance enhancement in a square channel heat exchanger(HX)using a passive technique is presented.Vortex turbulator insertion in a square channel HX as a passive technique is selected for thermal improvemen... Thermal performance enhancement in a square channel heat exchanger(HX)using a passive technique is presented.Vortex turbulator insertion in a square channel HX as a passive technique is selected for thermal improvement.The vortex turbulator of interest is discrete X-V baffles(XVB).The discrete XVBs are inserted in the square channel with the main aim of generating vortex flow.The vortex flow generated can support the enhanced convective heat transfer coefficient and also enhance HX performance.Effects of baffle configuration(type A and B),baffle size(w/H=0.05,0.10,0.15 and 0.20),baffle distance(e/H=1,1.5 and 2)and flow direction(±x air flow paths)on fluid flow and thermal topologies are numerically investigated by using a commercial code.As shown by the numerical results,the predicted flow configuration with the discrete XVB insertions,which include impinging and vortex streams,is found through the HX channel.The perturbing thermal boundary layer and greater air blending are also found through the HX channel inserted with the discrete XVB.These mechanisms promote and augment the convection heat transfer coefficient,heat transfer rate and rise thermal potentiality.The maximum Nusselt number of the channel with the baffles inserted is 11.01 times upper than that of the smooth channel,while the greatest thermal performance factor(TPF)is observed to be around 3.45. 展开更多
关键词 Discrete X-V baffles(XVB) passive technique numerical investigation vortex turbulators
下载PDF
Micro T-Mixer with Baffles: Effect of Baffle Height and Setting Angle on Mixing
10
作者 Miah Md Ashraful Alam Taichi Hirano +4 位作者 Yasutaka Hayamizu Takuya Masuda Tatsuki Hamada Shinichi Morita Manabu Takao 《Open Journal of Fluid Dynamics》 2023年第4期206-215,共10页
Chaotic mixing in eight different types of micro T-mixer flow has been studied experimentally and numerically. The present experimental study was performed to visualize two-liquid flows in a micro T-mixer with baffles... Chaotic mixing in eight different types of micro T-mixer flow has been studied experimentally and numerically. The present experimental study was performed to visualize two-liquid flows in a micro T-mixer with baffles. The Reynolds number, baffle height and setting angle were varied to investigate their effect on the mixing performance. Three micro T-mixer models were produced, which are several centimeters long and have a rectangular cross-section of few millimeters a side. The mixing of two-liquid was measured using the laser induced fluorescence (LIF) technique. Moreover, three-dimensional numerical simulations were conducted with the open-source CFD solver, OpenFOAM, for the same configuration as used in the experiments to investigate the detailed mechanism of the chaotic mixing. As a result, it was found that the mixing of two-liquid is greatly improved in the micro T-mixer with baffle. The baffle height and setting angle show a significant influence on the mixing performance. 展开更多
关键词 MICROMIXER baffles Liquid-Liquid Mixing LIF CFD
下载PDF
The Effect of Baffled Surface Flow Wetlands on Water Purification 被引量:5
11
作者 郭萧 张颖 +2 位作者 赵安娜 潘继征 李文朝 《Agricultural Science & Technology》 CAS 2010年第6期164-168,共5页
[Objective] The effect of baffled surface flow wetlands on water purification was studied in order to provide a reference for the ecological restoration of polluted river.[Method] Contents of some indexes like DO,TN,T... [Objective] The effect of baffled surface flow wetlands on water purification was studied in order to provide a reference for the ecological restoration of polluted river.[Method] Contents of some indexes like DO,TN,TP,NH+4-N,CODCr,SS,SD,etc.were determined in the band baffled surface flow wetlands with total area of 7 400 m2 at JiaLu riverside.[Result] Baffled surface flow wetlands could improve the effluent quality significantly,could enhance transparency and dissolved oxygen content and also could decrease SS content.The removal rate of TN was kept at more than 73% in summer and decreased to 23% in early winter;The removal rate of TP was little influenced by temperature,and it was kept at more than 77% in summer and still kept at more than 69% in autumn and winter;The removal rate of NH+4-N was kept at more than 83% in summer and decreased slightly in autumn and winter,but still kept at more than 75%;The removal rate of CODCr ranged from 14% to 50%.[Conclusion] Baffled surface flow wetlands could effectively improve the purification effect of surface flow wetlands,which is a feasible way for ecological restoration. 展开更多
关键词 baffled surface flow wetlands Wetland plants Purification effect
下载PDF
Performance comparison of heat exchangers using sextant/trisection helical baffles and segmental ones 被引量:5
12
作者 Yaping Chen Hongling Tang +2 位作者 JiafengWu Huaduo Gu Shifan Yang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第12期2892-2899,共8页
The shell side flow fields of both sextant and trisection helical baffle heat exchangers are presented on meridian and multilayer hexagon slices.It verifies that the performance of sextant schemes is better than those... The shell side flow fields of both sextant and trisection helical baffle heat exchangers are presented on meridian and multilayer hexagon slices.It verifies that the performance of sextant schemes is better than those of the other kinds of helical baffle heat exchangers.The main mechanisms are due to the restricted leakage flow in the minimized gaps with increased baffle number and by one row of tubes dampen the leakage flow in the circumferential overlapped area of the adjacent helical baffles.The performance features were simulated on two different angled sextant helical heat exchangers and each compared with two trisection ones of either identical helical pitch or identical incline angle.The results verified that the performances of helical heat exchangers are mainly determined by the helical pitch rather than the baffle incline angle.The average values of comprehensive index hoΔpo-1/3 of the trisection helical schemes T-24.1°and T-29.7°are correspondingly 3.47%and 3.34%lower than those of the sextant ones X-20°and X-25°with identical helical pitches.The comparison results show that the average values of shell side h.t.c.hoand comprehensive index hoΔpo-1/3 of the optimal dual helix sextant scheme DX30°are respectively 7.22%and 23.56%higher than those of the segment scheme S100. 展开更多
关键词 HEAT transfer Computational fluid dynamics Convection HELICAL baffle HEAT EXCHANGERS SEXTANT HELICAL baffles
下载PDF
Investigation of the Effects of Baffles on the Shallow Water Sloshing in A Rectangular Tank Using A 2D Turbulent ISPH Method 被引量:8
13
作者 Rahim SHAMSODDINI Bahador ABOLPUR 《China Ocean Engineering》 SCIE EI CSCD 2019年第1期94-102,共9页
Liquid sloshing is a common phenomenon in the liquid tanks transportation. Liquid waves lead to fluctuating forces on the tank wall. Uncontrolled fluctuations lead to large forces and momentums. Baffles can control th... Liquid sloshing is a common phenomenon in the liquid tanks transportation. Liquid waves lead to fluctuating forces on the tank wall. Uncontrolled fluctuations lead to large forces and momentums. Baffles can control these fluctuations. A numerical method, which has been widely used to model this phenomenon, is Smoothed Particle Hydrodynamics(SPH). The Lagrangian nature of this method makes it suitable for simulating free surface flows. In the present study, an accurate Incompressible Smoothed Particle Hydrodynamics(ISPH) method is developed and improved using the kernel gradient correction tensors, particle shifting algorithms, k–ε turbulence model, and free surface particle detectors. Comparisons with the experimental data approve the ability of the present algorithm for simulating shallow water sloshing. The main aim of this study is to investigate the effects of the vertical baffle on the damping of liquid sloshing. Results show that baffles number has a major role in sloshing fluctuation damping. 展开更多
关键词 SPH k–ε vertical baffle SHALLOW water SLOSHING free surface
下载PDF
Effects of Perforated Baffle on Reducing Sloshing in Rectangular Tank:Experimental and Numerical Study 被引量:11
14
作者 薛米安 林鹏智 +3 位作者 郑金海 马玉祥 苑晓丽 Viet-Thanh NGUYENa 《China Ocean Engineering》 SCIE EI CSCD 2013年第5期615-628,共14页
A liquid sloshing experimental rig driven by a wave-maker is designed and built to study liquid sloshing problems in a rectangular liquid tank with perforated baffle. A series of experiments are conducted in this expe... A liquid sloshing experimental rig driven by a wave-maker is designed and built to study liquid sloshing problems in a rectangular liquid tank with perforated baffle. A series of experiments are conducted in this experimental rig to estimate the free surface fluctuation and pressure distribution by changing external excitation frequency of the shaking table. An in-house CFD code is also used in this study to simulate the liquid sloshing in three-dimensional (3D) rectangular tank with perforated baffle. Good agreements of free surface elevation and pressure between the numerical results and the experimental data are obtained and presented. Spectral analysis of the time history of free surface elevation is conducted by using the fast Fourier transformation. 展开更多
关键词 liquid sloshing experimental study rectangular tank perforated baffle
下载PDF
Drawdown mechanism of light particles in baffled stirred tank for the KR desulphurization process 被引量:9
15
作者 Meng Li Yangbo Tan +2 位作者 Jianglong Sun De Xie Zeng Liu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第2期247-256,共10页
To improve the efficiency of the desulfurization process, the drawdown mechanism of light particles in stirred tank is studied in this paper. For both up and down pumping modes, the just drawdown speeds(Njd) of floati... To improve the efficiency of the desulfurization process, the drawdown mechanism of light particles in stirred tank is studied in this paper. For both up and down pumping modes, the just drawdown speeds(Njd) of floating particles in transformative Kanbara Reactor(KR) are measured in one and four baffled stirred tanks experimentally. Then numerical simulations with standard k-ε model coupled with volume of fluid model(VOF) and discrete phase model(DPM) are conducted to analyze the flow field at the just drawdown speed Njd. The torques on the impeller obtained from experiments and simulations agree well with each other, which indicates the validity of our numerical simulations. Based on the simulations, three main drawdown mechanisms for floating particles, the axial circulation, turbulent fluctuation and largescale eddies, are analyzed. It's found that the axial circulation dominates the drawdown process at small submergence(S = 1/4 T and 1/3 T) and the large-scale eddies play a major role at large submergence(S = 2/3 T and 3/4 T). Besides, the turbulent fluctuation affects the drawdown process significantly for up pumping mode at small submergence(S = 1/4 T and 1/3 T) and for down pumping mode at large submergence(S = 2/3 T and 3/4 T). This paper helps to provide a more comprehensive understanding of the KR desulphurizer drawdown process in the baffled stirred tank. 展开更多
关键词 LIGHT PARTICLES DRAWDOWN MECHANISM baffled stirred tank SUBMERGENCE Numerical simulations KR impeller
下载PDF
Effects of operational factors on soluble microbial products in a carrier anaerobic baffled reactor treating dilute wastewater 被引量:12
16
作者 FENG Huajun HU Lifang +3 位作者 SHAN Dan FANG Chengran HE Yonghua SHEN Dongsheng 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第6期690-695,共6页
The effects of feed strength, hydraulic residence time (HRT), and operational temperatures on soluble microbial product (SMP) production were investigated, to gain insights into the production mechanism. A carrier... The effects of feed strength, hydraulic residence time (HRT), and operational temperatures on soluble microbial product (SMP) production were investigated, to gain insights into the production mechanism. A carrier anaerobic baffled reactor (CABR) treating dilute wastewater was operated under a wide range of operational conditions, namely, feed strengths of 300-600 mg/L, HRTs of 9- 18 h, and temperatures of 10-28℃. Generally, SMP production increased with increasing feed strength and decreasing temperature. At high temperature (28℃), SMP production increased with decreasing HRT. As the temperature was decreased to 18 and 10℃, the SMP production was at its peak for 12 h HRT. Therefore, temperature could be an important determinant of SMP production along with HRT. A higher SMP to soluble chemical oxygen demand (SCOD) ratio was found at high temperature and long HRT because of complete volatile fatty acid degradation. SMP accounted for 50%-75% of the SCOD in the last chamber of the CABR. As a secondary metabolite, some SMP could be consumed at lower feed strength. 展开更多
关键词 carrier anaerobic baffled reactor dilute wastewater soluble microbial product hydraulic residence time feed strength temperature
下载PDF
Effects of Temperature and Hydraulic Residence Time (HRT) on Treatment of Dilute Wastewater in a Carrier Anaerobic Baffled Reactor 被引量:6
17
作者 HUA-JUN FENG LI-FANG HU +2 位作者 DAN SHAN CHENG-RAN FANG DONG-SHENG SHEN 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2008年第6期460-466,共7页
Objective To examine the effect of hydraulic residence time (HRT) on the performance and stability, to treat dilute wastewater at different operational temperatures in a carrier anaerobic baffled reactor (CABR), a... Objective To examine the effect of hydraulic residence time (HRT) on the performance and stability, to treat dilute wastewater at different operational temperatures in a carrier anaerobic baffled reactor (CABR), and hence to gain a deeper insight into microbial responses to hydraulic shocks on the base of the relationships among macroscopic performance, catabolic intermediate, and microcosmic alternation. Methods COD, VFAs, and microbial activity were detected with constant feed strength (300 mg/L) at different HRTs (9-18 h) and temperatures (10℃-28℃) in a CABR. Results The removal efficiencies declined with the decreases of HRTs and temperatures. However, the COD removal load was still higher at short HRT than at long HRT. Devastating reactor performance happened at temperature of 10℃ and at HRT of 9 h. HRTs had effect on the VFAs in the reactor slightly both at high and low temperatures, but the reasons differed from each other. Microbial activity was sensitive to indicate changes of environmental and operational parameters in the reactor. Conclusion The CABR offers to certain extent an application to treat dilute wastewater under a hydraulic-shock at temperatures from 10℃to 28℃. 展开更多
关键词 Carrier anaerobic baffled reactor Dilute wastewater Hydraulic residence time TEMPERATURE
下载PDF
Industrially Experimental Investigations and Development of the Curve-ROD Baffle Heat Exchanger 被引量:7
18
作者 严良文 吴金星 王志文 《Journal of Shanghai University(English Edition)》 CAS 2004年第3期337-341,共5页
The conventional heat exchanger with segmental baffles is prone to bring forth fluid-induced vibration of heat transfer tubes and increase the pressure drop of shell-side greatly at higher fluid flow velocity. In orde... The conventional heat exchanger with segmental baffles is prone to bring forth fluid-induced vibration of heat transfer tubes and increase the pressure drop of shell-side greatly at higher fluid flow velocity. In order to avoid the above defects, the ROD-baffle heat exchanger has been developed. However, its collocation of heat transfer tubes is conventionally in square, which leads to fewer heat transfer area per unit volume. Based on the ROD-baffle heat exchanger, a new type curve-ROD baffle has been developed, and an industrial investigation of the curve-ROD baffle heat exchanger with normal triangular collocation has been carried into execution. In this paper, two equations using the Reynolds number were acquired to predict the heat transfer coefficients of the shell-side and tube-side. The experimental results show that the shell-side heat transfer and pressure drop characteristics of the curve-ROD baffle heat exchanger are superior to those of the segmental baffle one. 展开更多
关键词 heat exchanger curve-ROD baffle heat transfer pressure drop experimental investigation.
下载PDF
Hydrodynamic characteristics of a four-compartment periodic anaerobic baffled reactor 被引量:5
19
作者 LIU Xiao-lei REN Nan-qi WAN Chun-li 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第10期1159-1165,共7页
Periodic anaerobic baffled reactor (PABR) is a novel reactor based on the design concept of anaerobic baffled reactor (ABR). Residence time distribution (RTD) studies on both clean and working reactors at the sa... Periodic anaerobic baffled reactor (PABR) is a novel reactor based on the design concept of anaerobic baffled reactor (ABR). Residence time distribution (RTD) studies on both clean and working reactors at the same hydraulic residence time (HRT) of 2 d were carded out to investigate the dead spaces and mixing patterns in PABRs at different organic loading rates (OLRs) in various switching manners and frequencies. The results showed that the fraction of dead space in PABR was similar to that in ABR, which was low in comparison with other reactor designs. Dead space may be divided into two categories, hydraulic and biological. In RTD studies without biomass, the hydraulic dead space in the PABR run in an "every second" switching manner with T = 2 d was the lowest whereas that in the PABR run in a T = ∞ (ABR) switching manner was the highest. The same trend was obtained with the total dead space in RTD studies with biomass no matter what the OLR was. Biological dead space was the major contributor to dead space but affected decreasingly at higher OLR whichever switching manner the PABR run in. The flow patterns within the PABRs were intermediate between plug-flow and perfectly mixed under all the conditions tested, 展开更多
关键词 dead space residence time distribution periodic anaerobic baffled reactor anaerobic processes wastewater treatment
下载PDF
Performance comparison for oil-water heat transfer of circumferential overlap trisection helical baffle heat exchanger 被引量:2
20
作者 王伟晗 程道来 +1 位作者 刘涛 刘颖昊 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第10期2720-2727,共8页
The performance tests were conducted on oil–water heat transfer in circumferential overlap trisection helical baffle heat exchangers with incline angles of 12°, 16°, 20°, 24° and 28°, and com... The performance tests were conducted on oil–water heat transfer in circumferential overlap trisection helical baffle heat exchangers with incline angles of 12°, 16°, 20°, 24° and 28°, and compared with a segmental baffle heat exchanger. The results show that the shell side heat transfer coefficient h_o and pressure drop Δp_o both increase while the comprehensive index h_o/Δp_o decreases with the increase of the mass flow rate of all schemes. And the shell side heat transfer coefficient, pressure drop and the comprehensive index ho/Δpo decrease with the increase of the baffle incline angle at a certain mass flow rate. The average values of shell side heat transfer coefficient and the comprehensive index h_o/Δp_o of the 12° helical baffled scheme are above 50% higher than those of the segmental one correspondingly, while the pressure drop value is very close and the ratios of the average values are about 1.664 and 1.596, respectively. The shell-side Nusselt number Nu_o and the comprehensive index Nu_o·Eu_(zo)^(-1) increase with the increase of Reynolds number of the shell side axial in all schemes, and the results also demonstrate that the small incline angled helical scheme has better comprehensive performance. 展开更多
关键词 performance experiments helical baffled heat exchangers circumferential overlap of baffles incline angle of baffle heat transfer enhancement
下载PDF
上一页 1 2 148 下一页 到第
使用帮助 返回顶部