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Experimental study on performance of passive and active solar stills in Indian coastal climatic condition

R. LALITHA NARAYANA, V. RAMACHANDRA RAJU

《能源前沿(英文)》 2020年 第14卷 第1期   页码 105-113 doi: 10.1007/s11708-018-0536-4

摘要: This present work is aimed to examine the effect of mass flow rate on distillate output and performance of a solar still in active mode. Outdoor experiments were conducted at the coastal town, Kakinada (16° 93′N/83° 33′E), Andhra Pradesh, India. A solar still with a 30° of fixed cover inclination, 1m of effective basin area, and a flat-plate collector (FPC) with an effective area of 2 m were used. An attempt was also made earlier in passive mode to optimize the water depth for the same solar still for maximum yield and distillation efficiency. For the passive still, it is observed that the capacity of heat storage and heat drop are significant parameters that affect the still performance. For the selected still design, the study reveals that 0.04 m water depth is the optimum value for specific climatic conditions. In the active solar still, with the optimum water depth, different flow rates of 0.5, 1 and 1.5 L/min are considered through FPC. It is observed that both the mass flow rate and the variation of internal heat transfer coefficients with the mass flow rate have a significant effect on the yield and performance of the still. The experimental results show that the combination of 1.5 L/min mass flow rate and an optimum water depth of 0.04m leads to a maximum yield for the active solar still. The enhanced yield of the active solar still is 57.55%, compared with that of the passive solar still, due to increase in area of radiation collection and more heat absorption rate.

关键词: distillation efficiency     solar still     heat transfer coefficient     water depth     optimum and mass flow rate    

Influence of mass air flow ratio on gas-particle flow characteristics of a swirl burner in a 29 MW pulverized

Rong YAN, Zhichao CHEN, Shuo GUAN, Zhengqi LI

《能源前沿(英文)》 2021年 第15卷 第1期   页码 68-77 doi: 10.1007/s11708-020-0697-9

摘要: In a gas/particle two-phase test facility, a three-component particle-dynamics anemometer was used to measure the characteristics of gas/particle two-phase flows in a 29 megawatt (MW) pulverized coal industrial boiler equipped with a new type of swirling pulverized coal burner. The distributions of three-dimensional gas/particle velocity, particle volume flux, and particle size distribution were measured under different working conditions. The mean axial velocity and the particle volume flux in the central region of the burner outlet were found to be negative. This indicated that a central recirculation zone was formed in the center of the burner. In the central recirculation zone, the absolute value of the mean axial velocity and the particle volume flux increased when the external secondary air volume increased. The size of the central reflux zone remained stable when the air volume ratio changed. Along the direction of the jet, the peak value formed by the tertiary air gradually moved toward the center of the burner. This tertiary air was mixed with the peak value formed by the air in the adiabatic combustion chamber after the cross-section of / = 0.7. Large particles were concentrated near the wall area, and the particle size in the recirculation zone was small.

关键词: industrial pulverized coal boiler     swirl burner     air/particle flow     particle dynamic analyzer (PDA)    

Effects of process parameters on surface roughness in abrasive waterjet cutting of aluminium

M. CHITHIRAI PON SELVAN, N. MOHANA SUNDARA RAJU, H. K. SACHIDANANDA

《机械工程前沿(英文)》 2012年 第7卷 第4期   页码 439-444 doi: 10.1007/s11465-012-0337-0

摘要:

Abrasive waterjet cutting is a novel machining process capable of processing wide range of hard-to-cut materials. Surface roughness of machined parts is one of the major machining characteristics that play an important role in determining the quality of engineering components. This paper shows the influence of process parameters on surface roughness (Ra) which is an important cutting performance measure in abrasive waterjet cutting of aluminium. Taguchi’s design of experiments was carried out in order to collect surface roughness values. Experiments were conducted in varying water pressure, nozzle traverse speed, abrasive mass flow rate and standoff distance for cutting aluminium using abrasive waterjet cutting process. The effects of these parameters on surface roughness have been studied based on the experimental results.

关键词: abrasive waterjet     aluminium     garnet     water pressure     mass flow rate     traverse speed     standoff distance    

Removal of arsenic by pilot-scale vertical flow constructed wetland

《环境科学与工程前沿(英文)》 2021年 第15卷 第4期 doi: 10.1007/s11783-021-1435-1

摘要:

• VFCWs are effective for the treatment of arsenic-containing wastewater.

关键词: Constructed wetland     Arsenic     Removal efficiency     Mass balance    

Convective mass transfer from a horizontal rotating cylinder in a slot air jet flow

Hongting MA , Dandan MA , Na YANG ,

《能源前沿(英文)》 2009年 第3卷 第3期   页码 289-296 doi: 10.1007/s11708-009-0019-8

摘要: The effects of air jet impinging on the mass transfer characteristics from a rotating spinning cylinder surface were experimentally investigated. The effects of rotational Reynolds number

关键词: air jet impinging     rotating cylinder     critical point     mass transfer characteristics    

Flow and mass balance analysis of eco-bio infiltration system

Marla C. MANIQUIZ, Lee-Hyung KIM, Soyoung LEE, Jiyeon CHOI

《环境科学与工程前沿(英文)》 2012年 第6卷 第5期   页码 612-619 doi: 10.1007/s11783-012-0448-1

摘要: A structured stormwater infiltration system was developed and constructed at a university campus and monitoring of storm events was performed during a one-year operation period. The flow and pollutant mass balances were analyzed and the overall efficiency of the system was assessed. While significant positive correlations were observed among rainfall, runoff and discharge volume ( = 0.93-0.99; <0.05), there was no significant correlations existed between rainfall, runoff, discharge volume and pollutant load. The system was more effective in reducing the runoff volume by more than 50% for small storm events but the difference between the runoff and discharge volume was significant even with rainfall greater than 10 mm. Results showed that the pollutant reduction rates were higher compared to the runoff volume reduction. Average pollutant reduction rates were in the range of 72% to 90% with coefficient of variation between 0.10 and 0.46. Comparable with runoff reduction, the system was more effective in reducing the pollutant load for small storm events, in the range of 80% to 100% for rainfall between 0 and 10 mm; while 65% to 80% for rainfall between 10 and 20 mm. Among the pollutant parameters, particulate matters was highly reduced by the system achieving only a maximum of 25% discharge load even after the entire runoff was completely discharged. The findings have proven the capability of the system as a tool in stormwater management achieving both flow reduction and water quality improvement.

关键词: best management practice     flow balance     low impact development     mass balance     nonpoint source     stormwater runoff    

Short-term prediction of influent flow rate and ammonia concentration in municipal wastewater treatment

Shuai MA, Siyu ZENG, Xin DONG, Jining CHEN, Gustaf OLSSON

《环境科学与工程前沿(英文)》 2014年 第8卷 第1期   页码 128-136 doi: 10.1007/s11783-013-0598-9

摘要: The prediction of the influent load is of great importance for the improvement of the control system to a large wastewater treatment plant. A systematic data analysis method is presented in this paper in order to estimate and predict the periodicity of the influent flow rate and ammonia (NH ) concentrations: 1) data filtering using wavelet decomposition and reconstruction; 2) typical cycle identification using power spectrum density analysis; 3) fitting and prediction model establishment based on an autoregressive model. To give meaningful information for feedforward control systems, predictions in different time scales are tested to compare the corresponding predicting accuracy. Considering the influence of the rainfalls, a linear fitting model is derived to estimate the relationship between flow rate trend and rain events. Measurements used to support coefficient fitting and model testing are acquired from two municipal wastewater treatment plants in China. The results show that 1) for both of the two plants, the periodicity affects the flow rate and NH concentrations in different cycles (especially cycles longer than 1 day); 2) when the flow rate and NH concentrations present an obvious periodicity, the decreasing of prediction accuracy is not distinct with increasing of the prediction time scales; 3) the periodicity influence is larger than rainfalls; 4) the rainfalls will make the periodicity of flow rate less obvious in intensive rainy periods.

关键词: influent load prediction     wavelet de-noising     power spectrum density     autoregressive model     time-frequency analysis     wastewater treatment    

Mechanism and control factors of hydrate plugging in multiphase liquid-rich pipeline flow systems: a

Shuwei ZHANG, Liyan SHANG, Zhen PAN, Li ZHOU, You GUO

《能源前沿(英文)》 2022年 第16卷 第5期   页码 747-773 doi: 10.1007/s11708-022-0830-z

摘要: There is nothing illogical in the concept that hydrates are easily formed in oil and gas pipelines owing to the low-temperature and high-pressure environment, although requiring the cooperation of flow rate, water content, gas-liquid ratio, and other specific factors. Therefore, hydrate plugging is a major concern for the hydrate slurry pipeline transportation technology. In order to further examine potential mechanisms underlying these processes, the present paper listed and analyzed the significant research efforts specializing in the mechanisms of hydrate blockages in the liquid-rich system, including oil-based, water-based, and partially dispersed systems (PD systems), in gathering and transportation pipelines. In addition, it summarized the influences of fluid flow and water content on the risk of hydrate blockage and discussed. In general, flow rate was implicated in the regulation of blockage risk through its characteristic to affect sedimentation tendencies and flow patterns. Increasing water content can potentiate the growth of hydrates and change the oil-water dispersion degree, which causes a transition from completely dispersed systems to PD systems with a higher risk of clogging. Reasons of diversity of hydrate plugging mechanism in oil-based system ought to be studied in-depth by combining the discrepancy of water content and the microscopic characteristics of hydrate particles. At present, it is increasingly necessary to expand the application of the hydrate blockage formation prediction model in order to ensure that hydrate slurry mixed transportation technology can be more maturely applied to the natural gas industry transportation field.

关键词: hydrate     flow rate     water content     mechanism of pipeline blockage     rich liquid phase system    

火灾中燃料失重速率与烟气向远距离处迁移关系的实验研究

冯文兴,杨立中,方廷勇,黄锐,范维澄

《中国工程科学》 2005年 第7卷 第1期   页码 81-85

摘要:

通过不同燃料在模拟房间—走廊结构实验装置中的燃烧实验,较系统地揭示了不同材料燃烧时失重速率变化与远距离处烟气迁移速度和CO浓度的关系。实验得到了不同燃料燃烧时的失重速率曲线。研究发现,多数燃料的烟气传播速度与失重速率呈线性变化的关系,油料和布料的烟气传播速度对质量失重速率的变化非常敏感;某些燃料燃烧产生有毒成分的峰值迁移到远距离处需要较长的时间。

关键词: 火灾     失重速率     远距离处     迁移速度     烟气毒性    

An integrated approach to site-specific management zone delineation

Yuxin MIAO, David J. MULLA, Pierre C. ROBERT

《农业科学与工程前沿(英文)》 2018年 第5卷 第4期   页码 432-441 doi: 10.15302/J-FASE-2018230

摘要:

Dividing fields into a few relatively homogeneous management zones (MZ) is a practical and cost-effective approach to precision agriculture. There are three basic approaches to MZ delineation using soil and/or landscape properties, yield information, and both sources of information. The objective of this study is to propose an integrated approach to delineating site-specific MZ using relative elevation, organic matter, slope, electrical conductivity, yield spatial trend map, and yield temporal stability map (ROSE-YSTTS) and evaluate it against two other approaches using only soil and landscape information (ROSE) or clustering multiple year yield maps (CMYYM). The study was carried out on two no-till corn-soybean rotation fields in eastern Illinois, USA. Two years of nitrogen (N) rate experiments were conducted in Field B to evaluate the delineated MZs for site-specific N management. It was found that in general the ROSE approach was least effective in accounting for crop yield variability (8.0%–9.8%), while the CMYYM approach was least effective in accounting for soil and landscape (8.9%–38.1%), and soil nutrient and pH variability (9.4%–14.5%). The integrated ROSE-YSTTS approach was reasonably effective in accounting for the three sources of variability (38.6%–48.9%, 16.1%–17.3% and 13.2%–18.7% for soil and landscape, nutrient and pH, and yield variability, respectively), being either the best or second best approach. It was also found that the ROSE-YSTTS approach was effective in defining zones with high, medium and low economically optimum N rates. It is concluded that the integrated ROSE-YSTTS approach combining soil, landscape and yield spatial-temporal variability information can overcome the weaknesses of approaches using only soil, landscape or yield information, and is more robust for MZ delineation. It also has the potential for site-specific N management for improved economic returns. More studies are needed to further evaluate their appropriateness for precision N and crop management.

关键词: economically optimum nitrogen rate     fuzzy cluster analysis     precision nitrogen management     site-specific management     soil landscape property     yield map    

Chemically reactive solute transfer in a boundary layer slip flow along a stretching cylinder

Swati Mukhopadhyay

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 385-391 doi: 10.1007/s11705-011-1101-4

摘要: This paper presents the distribution of a solute undergoing a first order chemical reaction in an axisymmetric laminar boundary layer flow along a stretching cylinder. Velocity slip condition at the boundary is used instead of no-slip condition. Similarity transformations are used to convert the partial differential equations corresponding to momentum and concentration into highly nonlinear ordinary differential equations. Numerical solutions of these equations are obtained by the shooting method. The velocity decreases with increasing slip parameter. The skin friction as well as the mass transfer rate at the surface is larger for a cylinder than for a flat plate.

关键词: boundary layer     stretching cylinder     partial slip     mass transfer     similarity solution    

Influence of different oil feed rate on bituminous coal ignition in a full-scale tiny-oil ignition burner

Chunlong LIU, Qunyi ZHU, Zhengqi LI, Qiudong ZONG, Xiang ZHANG, Zhichao CHEN

《能源前沿(英文)》 2013年 第7卷 第3期   页码 406-412 doi: 10.1007/s11708-013-0266-6

摘要: To reduce oil consumption during firing-up and partial-load operation, a tiny-oil ignition burner has been recommended. Through reacting-flow experiments performed on a full-scale experimental setup, the influence of different oil flow rates on bituminous coal combustion as well as flow rates without coal feed was analyzed. The ignition burner is identical to that normally used in an 800 MWe utility boiler. Under operating conditions with flow rates of 50, 100, and 150 kg/h, gas temperature distributions were measured in the burner. At the equivalent measuring points at the exits of the first and second combustion chambers, these distributions remained almost unchanged under a constant coal feed rate of 4 t/h. However on the burner centerline, distributions increased slightly with increasing flow rate. Different gas concentrations were measured at the center of the burner exit. For instance, the O concentration at the burner exit varied from 0.01% to 0.31% whereas CO concentrations were more than 10000 ppm. At the same coal feed rate of 4 t/h, burner resistances are 480, 600, and 740 Pa for oil flow rates of 50, 100, and 150 kg/h, respectively.

关键词: ignition     coal     burner     boiler     oil flow rate    

工业生态系统与食物网——以一种基于生态学的质量流分析方法建立中国钢铁制造业模型 Article

Stephen M. Malone, Marc J. Weissburg, Bert Bras

《工程(英文)》 2018年 第4卷 第2期   页码 209-217 doi: 10.1016/j.eng.2018.03.008

摘要:

物质与能量在自然系统和工业系统之间的转换,为推导这些系统之间的相互作用提供了一种标准。考察这些流动是谈论工业如何影响环境的基本内容。我们认为体现可持续性的生物系统提供的方法和原理能为组织工业活动带来更多有用的方法。把这些生物学方法运用到钢铁制造中,可有效利用材料、减少废料并可利用目前的技术减少能源需求。在本文中,我们采用基于系统的质量流分析,利用生态学原理来考察中国钢铁行业中的材料随着时间变化产生的结构与流动方面的变化。运用现有数据,我们的分析结果表明中国钢铁制造业已在单元过程层面提高了能源效率及可持续利用程度,但合理地组织钢铁制造生态系统仍有进步空间。我们的结果表明通过协同行业的智能化布局利用钢铁制造中产生的废料,中国未来的钢铁行业将在减少废料的同时更好地体现生态系统的成熟度与健康状况。

关键词: 生态学网络分析     质量流分析     钢铁制造    

Mass Transfer-Promoted Fe2+/Fe3+ Circulation Steered by 3D Flow-Through Co-Catalyst System Toward Sustainable

Weiyang Lv,Hao Li,Jinhui Wang,Lixin Wang,Zenglong Wu,Yuge Wang,Wenkai Song,Wenkai Cheng,Yuyuan Yao,

《工程(英文)》 doi: 10.1016/j.eng.2023.06.010

摘要: Realizing fast and continuous generation of reactive oxygen species (ROSs) via iron-based advanced oxidation processes (AOPs) is significant in the environmental and biological fields. However, current AOPs assisted by co-catalysts still suffer from the poor mass/electron transfer and non-durable promotion effect, giving rise to the sluggish Fe2+/Fe3+ cycle and low dynamic concentration of Fe2+ for ROS production. Herein, we present a three-dimensional (3D) macroscale co-catalyst functionalized with MoS2 to achieve ultra-efficient Fe2+ regeneration (equilibrium Fe2+ ratio of 82.4%) and remarkable stability (more than 20 cycles) via a circulating flow-through process. Unlike the conventional batch-type reactor, experiments and computational fluid dynamics simulations demonstrate that the optimal utilization of the 3D active area under the flow-through mode, initiated by the convection-enhanced mass/charge transfer for Fe2+ reduction and then strengthened by MoS2-induced flow rotation for sufficient reactant mixing, is crucial for oxidant activation and subsequent ROS generation. Strikingly, the flow-through co-catalytic system with superwetting capabilities can even tackle the intricate oily wastewater stabilized by different surfactants without the loss of pollutant degradation efficiency. Our findings highlight an innovative co-catalyst system design to expand the applicability of AOPs based technology, especially in large-scale complex wastewater treatment.

关键词: Advanced oxidation processes     3D co-catalyst     Flow-through mode     Enhanced mass transfer     Complex wastewater treatment    

旅客机环境控制系统优化研究

方林,王浚

《中国工程科学》 2006年 第8卷 第1期   页码 77-80

摘要:

为了选择经济高效的旅客机环境控制系统,对现役各种旅客机采用的环境控制系统方案进行了优化设计和比较,分别建立了二轮简单式低压除水系统、三轮升压式高压除水系统和四轮升压式高压除水系统(又称冷凝循环制冷系统)的优化设计数学模型,以起飞燃油质量代偿损失为目标函数,采用广义乘子法结合单纯形加速法求解,优化结果可作为设计研究旅客机环境控制系统的理论依据。

关键词: 旅客机     环境控制     优化设计    

标题 作者 时间 类型 操作

Experimental study on performance of passive and active solar stills in Indian coastal climatic condition

R. LALITHA NARAYANA, V. RAMACHANDRA RAJU

期刊论文

Influence of mass air flow ratio on gas-particle flow characteristics of a swirl burner in a 29 MW pulverized

Rong YAN, Zhichao CHEN, Shuo GUAN, Zhengqi LI

期刊论文

Effects of process parameters on surface roughness in abrasive waterjet cutting of aluminium

M. CHITHIRAI PON SELVAN, N. MOHANA SUNDARA RAJU, H. K. SACHIDANANDA

期刊论文

Removal of arsenic by pilot-scale vertical flow constructed wetland

期刊论文

Convective mass transfer from a horizontal rotating cylinder in a slot air jet flow

Hongting MA , Dandan MA , Na YANG ,

期刊论文

Flow and mass balance analysis of eco-bio infiltration system

Marla C. MANIQUIZ, Lee-Hyung KIM, Soyoung LEE, Jiyeon CHOI

期刊论文

Short-term prediction of influent flow rate and ammonia concentration in municipal wastewater treatment

Shuai MA, Siyu ZENG, Xin DONG, Jining CHEN, Gustaf OLSSON

期刊论文

Mechanism and control factors of hydrate plugging in multiphase liquid-rich pipeline flow systems: a

Shuwei ZHANG, Liyan SHANG, Zhen PAN, Li ZHOU, You GUO

期刊论文

火灾中燃料失重速率与烟气向远距离处迁移关系的实验研究

冯文兴,杨立中,方廷勇,黄锐,范维澄

期刊论文

An integrated approach to site-specific management zone delineation

Yuxin MIAO, David J. MULLA, Pierre C. ROBERT

期刊论文

Chemically reactive solute transfer in a boundary layer slip flow along a stretching cylinder

Swati Mukhopadhyay

期刊论文

Influence of different oil feed rate on bituminous coal ignition in a full-scale tiny-oil ignition burner

Chunlong LIU, Qunyi ZHU, Zhengqi LI, Qiudong ZONG, Xiang ZHANG, Zhichao CHEN

期刊论文

工业生态系统与食物网——以一种基于生态学的质量流分析方法建立中国钢铁制造业模型

Stephen M. Malone, Marc J. Weissburg, Bert Bras

期刊论文

Mass Transfer-Promoted Fe2+/Fe3+ Circulation Steered by 3D Flow-Through Co-Catalyst System Toward Sustainable

Weiyang Lv,Hao Li,Jinhui Wang,Lixin Wang,Zenglong Wu,Yuge Wang,Wenkai Song,Wenkai Cheng,Yuyuan Yao,

期刊论文

旅客机环境控制系统优化研究

方林,王浚

期刊论文