Multi-objective Optimization Based on Unsteady Analysis Considering the Efficiency and Radial Force of a Single-Channel Pump for Wastewater Treatment

A multidisciplinary optimization was conducted to simultaneously improve the efficiency and reduce the radial force of a single-channel pump for wastewater treatment. A hybrid multi-objective evolutionary algorithm was coupled with a surrogate model to optimize the geometry of the single-channel pump volute. Steady and unsteady Reynolds-averaged Navier-Stokes equations with a shear stress transport turbulence model were discretized using finite volume approximations and were then solved on tetrahedral grids to analyze the flow in the single-channel pump. The three objective functions represented the total efficiency, the sweep area of the radial force during one revolution, and the distance of the mass center of sweep area from the origin while the two design variables were related to the cross-sectional area of the internal flow of the volute. Latin hypercube sampling was employed to generate twelve design points within the design space, and response surface approximation models were constructed as surrogate models for the objectives based on the values of the objective function at the given design points. A fast non-dominated sorting genetic algorithm for local search was coupled with the surrogate models to determine the global Pareto-optimal solutions. The trade-off between the objectives was determined and was described in terms of the Pareto-optimal solutions. The results of the multi-objective optimization showed that the optimum design simultaneously improved the efficiency and reduced the radial force relative to those of the reference design.

Investigation of the hydrodynamics of slug flow in airlift pumps

A slug flow model considering the dispersed bubbles entrained from the tail of Taylor bubble(TB) and recoalesced with the successive TB was proposed. Experiment was conducted to test the validity of this model by using a high-speed camcorder and particle image velocimetry(PIV). It was found that the model was valid for predicting the characteristics of slug flow in airlift pump within average error of 14%. Moreover, large pipe diameter was found to accelerate the rise velocity of TB and decreases void fraction in liquid slug by a small margin.

Bubble size modeling approach for the simulation of bubble columns

The constant bubble size modeling approach(CBSM)and variable bubble size modeling approach(VBSM)are frequently employed in Eulerian–Eulerian simulation of bubble columns.However,the accuracy of CBSM is limited while the computational efficiency of VBSM needs to be improved.This work aims to develop method for bubble size modeling which has high computational efficiency and accuracy in the simulation of bubble columns.The distribution of bubble sizes is represented by a series of discrete points,and the percentage of bubbles with various sizes at gas inlet is determined by the results of computational fluid dynamics(CFD)–population balance model(PBM)simulations,whereas the influence of bubble coalescence and breakup is neglected.The simulated results of a 0.15 m diameter bubble column suggest that the developed method has high computational speed and can achieve similar accuracy as CFD–PBM modeling.Furthermore,the convergence issues caused by solving population balance equations are addressed.

A novel quantificational assessment method of frothers effect on bubble characteristics

A new visual method for quantitative measurement of frothers effect and flotation efficiency was presented. A self-designed electrolytic cell was chosen as the reaction environment with sodium chloride (NaCl) as the electrolyte. Constant current, supplied by a self-designed power supplier and fixed cathode and anode equipment, guaranteed the constant bubble volume per unit time. Even aperture of the cathode material guaranteed the original bubbles size to be uniform. Bubble generating equipment was connected with a microscopical camera. Statistic data collected by high speed charge-coupled device (CCD) and processed by software Sigmascan and Matlab could reflect bubble characteristics. The efficiency of dipropylene glycol monomethyl ether (DPM) and tripropylene glycol n-butyl ethel (TPnB) were measured at the same condition, and 2×10-4 mol/L and 5×10-2 mol/L were found to be the inflexions of bubble size changes.

Mathematical model of absorption and hybrid heat pump

Recovering waste heat from industrial processes is bene ficial in order to reduce the primary energy demands and heat pumps can be used to this purpose.Absorption heat pumps are energy-saving and environment-friendly because use working fluids that do not cause ozone depletion and can reduce the global warming emissions.The hybrid heat pump processes combine the conventional vapor-compression and the absorption heat pump cycles.Studies about the simulations and modeling of hybrid heat pumps are few in literature.In this research a mathematical model for single effect absorption and hybrid heat pump is carried out with Chem Cad? 6.0.1.LiBr–H_2O is used as working fluid while electrolytic NRTL and electrolytes latent heat are used as thermodynamic model due to the better results.Binary parameters of activity coef ficients are regressed from experimental vapor pressure data while default constants are used for the solubility expressions.A design of heat pumps is developed and a new modeling of generator is analyzed.The coef ficient of performance of absorption heat pump and hybrid heat pump is equal to 0.7 and 0.83 respectively.For absorption heat pump a sensitivity analysis is carried out to evaluate the effect of temperature and pressure generator,the concentration of Li–Br solution on coef ficient of performance,cooling capacity and working fluid temperature.For hybrid heat pump,the different coef ficients of performance,the primary energy ratio,the generator heat,and the compressor power are analyzed for different values of compressor proportion.Results show that comparing the two systems the hybrid pump allows to save more primary energy,costs and carbon dioxide emissions with respect to absorption heat pump with the increasing of compressor proportion parameter.Future researches should focus on the construction of this heat pumps integrated in chemical processes as a biogas plant or trigeneration systems.

The Laser Action of a Yb:CLNGG Crystal with an Efficiency Approaching Its Quantum Defect Imposed Limit

Continuous-wave laser operation is demonstrated at room temperature with a new disordered Yb:CLNGG crystal.A maximum output power of 5.05 W is generated with 7.8 W of pump power absorbed in the crystal,resulting in an optical-to-optical efficiency of 65%,whereas the slope efficiency is determined to be 92%,approaching the limit imposed by the quantum defect in the laser emission process.

Experimental Investigation of Organic Rankine Cycle (ORC) for Low Temperature Geothermal Fluid: Effect of Pump Rotation and R-134 Working Fluid in Scroll-Expander

Organic Rankine Cycle(ORC)is one of the solutions to utilize a low temperature geothermal fluid for power generation.The ORC system can be placed at the exit of the separator to extract energy from brine.Furthermore,one of the main components of the system and very important is the pump.Therefore,in this research,the pump rotation is examined to investigate the effect on power output and energy efficiency for low temperature geothermal fluid.The rotation is determined by using an inverter with the following frequencies:7.5,10,12.5,15 and 17.5 Hz,respectively.R-134 working fluid is employed with 373.15 K evaporator temperature in relation to the low temperature of the geothermal fluid.Furthermore,the condenser temperature and fluid pressure were set up to 293.15 K and 5×10^(5) Pa,respectively.This research uses a DC generator with a maximum power of 750 Watt and the piping system is made from copper alloy C12200 ASTM B280 with size 1.905×10^(−2) m and a thickness of 8×10^(−4) m.The results showed that there is an increase in mass flow rate,enthalpy and generator power output along with increasing pump rotation.In addition,it showed that the maximum generator output power was 377.31 Watt at the highest pump rotation with a frequency of 17.5 Hz.

Bubble Pump Models Verification Based on the Experimental Results

DAR （diffusion absorption refrigeration） cycle is driven by heat and has no moving parts. It is based on refrigerant and absorbent as the working fluid together with hydrogen as an auxiliary inert gas. To circulate the working fluid without a mechanical pump, the diffusion absorption cycle relies on a bubble pump. Experimental system was designed and operated. Its aim was to investigate the performance of a bubble pump operating with three lifting tubes. The experimental results of the system were compared to existing models. The comparison showed that there was a bad agreement between the experimental and the theoretical results.

Quantifying the Efficiency Advantages of High Viscosity Index Hydraulic Fluids

By providing higher in-use viscosity at elevated operating temperatures,hydraulic fluids with high viscosity index improve the efficiency of the hydraulic system.For mobile hydraulic equipment this efficiency can be quantified as an increase in fuel economy.This paper reviews the research that demonstrates these efficiency advantages in gear,vane and piston pumps and presents a method for predicting the overall fuel economy for a fleet of hydraulic equipment in operation.Finally a `Maximum Efficiency Hydraulic Fluid’ performance definition is presented which will enable an equipment operator to easily improve the performance of the system and reduce fuel consumption.

Numerical and Experimental Investigation of High-efficiency Axial-flow Pump

The experimental investigation of axial-flow pump has been rapidly developed to meet the needs of South-to-North Water Diversion Project of China. Owing to the boundary conditions of hub, blade tip clearance, much of the physical phenomena and laws involved in this complex flow field can＇t be fully determined. The flow characteristics of the high efficiency axial-flow pump have been simulated by RNG k-e turbulence model and SIMPLEC arithmetic based on FLUENT software. Numerical results indicate that the data from the prediction show agreement with the experimental results, static pressure on pressure side of blades increases slightly at circumferential direction with radius increasing, and keep almost constant at the same radial while increasing gradually from inlet to exit on the suction side along flow direction at design conditions. The static pressure, total pressure and velocity at inlet, impeller outlet and vane outlet were measured by a five-hole probe, and a contrastive experiment was done to investigate the influence of hub leakage. The experimental results show that inlet flow is almost axial and the prerotation is very small at various conditions. The meridional velocity and circulation distribution are almost identical at impeller outlet at design conditions due to steady flow and high efficiency. The residual circulation exits at downstream of the guide vane, and the circumferential velocity component increases linearly from hub to tip at small flow rate conditions. Hub leakage in adjustable blades results in the decrease of the meridional velocity and circulation at blade exit near hub. The results of numerical simulation and experiments supply important flow structure information for the high-efficiency axial-flow pump.

Experimental assessment of two-phase bubble pump for solar water heating

The research goal is to develop a new solar water heater system(SWHS) that uses a solar bubble pump instead of an electric pump.The pump is powered by the steam produced from an evacuated tube collector.Therefore,heat could be transferred downward from the collector to a hot water storage tank.The designed system consists of two sets of heat-pipe evacuated tube collectors,a solar bubble pump installed at an upper level and a water storage tank with a heat exchanger at a lower level.Discharge heads of 1 and 5 m were tested.The bubble pump could operate at the collector temperature of about 90-100 ℃ and vapor gage pressure of 80-90 kPa.It is found that water circulation within the SWHS depends on the incident solar intensity and system discharge head.Experimental investigations are conducted to obtain the system thermal efficiencies from the hourly,daily and long-term performance tests.The thermal performance of the proposed system is compared with conventional solar water heaters.The results show that the proposed system achieves system characteristic efficiency of 10% higher than that of the conventional systems using electric pump if taking the consumption of electric power into account.And the former is a zero carbon system.

Distribution characteristics and impact on pump＇s efficiency of hydro-mechanical losses of axial piston pump over wide operating ranges

A novel performance model of losses of pump was presented,which allows an explicit insight into the losses of various friction pairs of pump.The aim is to clarify that to what extent the hydro-mechanical losses affect efficiency,and to further gain an insight into the variation and distribution characteristics of hydro-mechanical losses over wide operating ranges.A good agreement is found in the comparisons between simulation and experimental results.At rated speed,the hydro-mechanical losses take a proportion ranging from 87% to 89% and from 68% to 97%,respectively,of the total power losses of pump working under 5 MPa pressure conditions,and 13% of full displacement conditions.Furthermore,within the variation of speed ranging from 48% to 100% of rated speed,and pressure ranging from 14% to 100% of rated pressure,the main sources of hydro-mechanical losses change to slipper swash plate pair and valve plate cylinder pair at low displacement conditions,from the piston cylinder pair and slipper swash plate pair at full displacement conditions.Besides,the hydro-mechanical losses in ball guide retainer pair are found to be almost independent of pressure.The derived conclusions clarify the main orientations of efforts to improve the efficiency performance of pump,and the proposed model can service for the design of pump with higher efficiency performance.

Effects of 946-nm thermal shift and broadening on Nd^(3+):YAG laser performance

Spectroscopic properties of flashlamp pumped Nd^3＋：YAG laser are studied as a function of temperature in a range from-30℃ to 60℃. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission within the respective intermanifold transitions of ^4F3/2→^4I9/2are investigated. The 946.0-nm line shifts toward the shorter wavelength and broadens. In addition, the threshold power and slope efficiency of the 946.0-nm laser line are quantified with temperature.The lower the temperature, the lower the threshold power is and the higher the slope efficiency of the 946.0-nm laser line is,thus the higher the laser output is. This phenomenon is attributed to the ion-phonon interaction and the thermal population in the ground state.

Dynamic simulation and efficiency analysis of beam pumping system

An improved whole model of beam pumping system was built. In the detail, for surface transmission system(STS), a new mathematical model was established considering the influence of some factors on the STS's torsional vibration, such as the time variation characteristic of equivalent stiffness of belt and equivalent rotational inertia of crank. For the sucker rod string(SRS), an improved mathematical model was built considering the influence of some parameters on the SRS's longitudinal vibration, such as the nonlinear friction of plunger, hydraulic loss of pump and clearance leakage. The dynamic response and system efficiency of whole system were analyzed. The results show that there is a jumping phenomenon in the amplitude frequency curve, and the system efficiency is sensitive to motor power, pump diameter, stroke number, ratio of gas and oil, and submergence depth. The simulation results have important significance for improving the efficiency of beam pumping system.

Design and application of electric oil pump in automatic transmission for efficiency improvement and start–stop function

For the purpose of improving efficiency and realizing start–stop function, an electric oil pump(EOP) is integrated into an 8-speed automatic transmission(AT). A mathematical model is built to calculate the transmission power loss and the hydraulic system leakage. Based on this model, a flow-based control strategy is developed for EOP to satisfy the system flow requirement. This control strategy is verified through the forward driving simulation. The results indicate that there is a best combination for the size of mechanical oil pump(MOP) and EOP in terms of minimum energy consumption. In order to get a quick and smooth starting process, control strategies of the EOP and the on-coming clutch are proposed. The test environment on a prototype vehicle is built to verify the feasibility of the integrated EOP and its control strategies. The results show that the selected EOP can satisfy the flow requirement and a quick and smooth starting performance is achieved in the start–stop function. This research has a high value for the forward design of EOP in automatic transmissions with respect to efficiency improvement and start–stop function.

A Numerical Study on the Responses of Wave-Driven Circulation to Varying Incident Wave Forcing and Reef Morphology in A Reef-Lagoon-Channel System

Wave-driven circulation in a reef-lagoon-channel system has significant ecological,geomorphological,and environmental implications.However,there is still research gap in fully understanding the responses of wave-driven circulation in the system to varying incident wave forcing and reef morphology.To better interpret the wave-current process inside an idealized reef-lagoon-channel configuration,a numerical model based on the horizontally two-dimensional(2DH)fully nonlinear Boussinesq equations is presented in this study.The adopted model is firstly validated by a published laboratory dataset for wave height,wave setup and mean current in the system.Subsequently,the impacts of wave forcing(incident wave height,incident wave period,reef-flat wave level)and reef morphological(fore-reef slope,cross-shore reef-flat width,channel width,reef roughness)factors that are not fully considered in the previous laboratory studies are reported through the numerical simulations in this study.Finally,the model is applied to analyze the wave pump efficiency parameter in the system,and an empirical equation to predict this parameter is also proposed.

Performance Prediction of an Optimized Centrifugal Pump with High Efficiency

The main structural parameters of the IR100-80-100A type chemical centrifugal pump have been optimized by means of an orthogonal test approach.The centrifugal pump has been modeled using the CFturbo software,and 16 sets of orthogonal-test schemes have been defined on the basis of 4 parameters,namely,the blade number,blade outlet angle,impeller outlet diameter,and impeller outlet width.Such analysis has been used to determine the influence of each index parameter on the pump working efficiency and identify a set of optimal combinations of such parameters.The internalflowfield in the centrifugal pump has been simulated by using the PumLinx software.These numerical results have shown that,compared with the prototype pump,the outlet pressure and shaft power of the optimized pump can be significantly reduced,and the pump working efficiency can be improved by 5.59%.In the present study,some arguments are also provided to demonstrate that,with respect to other optimization methods,the orthogonal test approach is more convenient,and requires less test times.

Comparative Analysis of Two Energy-Efficient Technologies Used in the Shanghai Tower

Climate change continues to affect the lives of individuals across the world, creating a rise in demand for new technologies that can slow down the impacts of climate change. Shanghai, one of the largest cities in the world, has one of the highest carbon emission levels. In recent years, the research and development of energy-efficient technologies have gained more and more attention. The Shanghai Tower is a pioneer in green building design and a prominent example of Shanghai’s efforts towards low-carbon city development. In this paper, two technologies within the Shanghai Tower—ground source heat pumps (GSHP) and double skin facades (DSF)—will be analyzed. The paper will consist of firstly an investigation of the principles of the technologies, and then analysis, evaluation, and comparison of their respective characteristics. While both GSHP and DSF are used for sustainable purposes, the effectiveness of technologies depends on what environment the technology is used in and what purpose they serve. The evaluation of GSHP and DSF will be based on their performances under Shanghai’s climate and whether they contribute to the purposes of the Shanghai Tower.

Influence of Condensing Temperature on Heat Pump Efficiency

The thermodynamic aspect of a compression type heat pump （HP） is briefly described and special attention is given to investigation of condensing temperature influence on heat pump efficiency in heating mode, expressed by its coefficient of performance （COP）. Heat pumps are usually applied for the purposes of heating and cooling of energy efficient buildings where they have advantages in low-temperature systems, as it is well documented in the paper. The comparison of real thermodynamic processes with thermodynamically most favorable Camot＇s process is made. The results in the paper show that COP is diminishing with increasing of condensing temperature and also depends on real properties of working fluids. The impact of compressor efficiency for two real working media is also analyzed in the paper. There is significant diminishing of COP with diminishing of compressor efficiency. The intension of the paper is to help better understanding of this very effective and prosperous technology, and to encourage its development, production, and efficient application.

Assessment of Diyarbaklr Basalt Aquifer Hydrogeological Analyzed and Obtains Thematic Maps with GIS Geostatistical Analyst Tool

Diyarbaklr basalt aquifer is volcanic-rock aquifers which contain high quality water. It was main resources for Diyarbaklr city center drinking supply up to 2005. Somewhere, basalt aquifer groundwater is still used for irrigation in rural areas of Diyarbaklr city. In the study, Diyarbaklr city center＇s （which is located on the Tigris river basin） basalt aquifer groundwater potentials and hydrogeological features are examined and modeled by using GIS programmer. Firstly, general geological data, meteorological data and general information about natural water sources are collected together, afterwards, logs of well drilled by public institutions and private individuals within the Diyarbaklr city center are analyzed. Static water level, dynamic water level and well pumps yields are classified in these logs. Then, thematic maps produced with the help of Arc Info Professional GIS programmer with geostatistical analyst tool. Groundwater source potential of Diyarbaktr is examined by means of these thematic maps. In hydrogeological research, productivity by aquifer features, water retention capacity and groundwater level data evaluated with geological structure of area are taken into consideration.