scholarly journals Assessment of the efficiency of oxygen absorption in rotor-pulsating apparatus

2018 ◽  
pp. 117-124 ◽  
Author(s):  
Oleksandr Obodovych ◽  
Vitalii Sydorenko
Keyword(s):  
Experimental Data ◽  
Energy Efficiency ◽  
Rotational Speed ◽  
Absorption Rate ◽  
Sodium Sulfide ◽  
Chemical Oxidation ◽  
Model Solution ◽  
Oxygen Absorption ◽  
Oxygen Absorption Rate ◽  
Aeration Conditions

This work presents the results of a study of the oxygen absorption rate in water solutions in the setup consisting of a jet unit and disperser-mixer, which is a rotor-pulsating apparatus. The purpose of the work was to evaluate the efficiency of the rotor-pulsating apparatus in the aeration of aqueous solutions. The experimental data were obtained by the method of chemical oxidation of sodium sulfide, part of the model solution, with air oxygen,. The influence of the rotor rotational speed on the oxygen absorption rate was determined by experiments. A comparison of aeration conditions, sulfite number, and energy efficiency in relation to the corresponding characteristics of some pneumatic and mechanical aerators found in the literature is provided.

Stress Relaxation in Rubber II. Simultaneous Oxygen Absorption

1956 ◽  
Vol 29 (1) ◽  
pp. 250-262
Author(s):  
S. Baxteh ◽  
P. D. Potts ◽  
H. A. Vodden
Keyword(s):  
Stress Relaxation ◽  
Absorption Rate ◽  
Oxidative Degradation ◽  
Oxygen Absorption ◽  
Network System ◽  
Antioxidant Action ◽  
Basic Study ◽  
Aging Studies ◽  
Oxygen Absorption Rate ◽  
A New Technique

Abstract In any serious study of antioxidant action, it is essential that the oxygen absorption rate of a protected rubber be determined and the changes in the network system caused by the oxygen be assessed. This information is normally obtained from separate oxygen absorption and aging studies. A method is described in this article which enables simultaneous measurements of oxygen absorption and stress relaxation to be made on a given rubber sample. A number of antioxidants have been compounded with natural rubber and, from the results, an estimate is made of the molecules of oxygen absorbed per rubber chain cut. This is found to vary with the antioxidant, although some difficulties of interpretation are pointed out. Variations of deactivating effect among the antioxidants shows clearly that any attempt to understand oxidative degradation in terms of oxygen absorption or decay in physical properties alone is not possible. The method provides a new technique that is of value in any basic study of antioxidant action in elastomers.

Optimization of friction stir welding process parameters for AA6063-ETP copper using central composite design

2020 ◽  
Vol 17 (4) ◽  
pp. 491-507 ◽  
Author(s):  
Nitin Panaskar ◽  
Ravi Prakash Terkar
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Process Parameters ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Tool Rotational Speed ◽  
Content Type ◽  
Friction Stir ◽  
Central Composite

Purpose Recently, several studies have been performed on lap welding of aluminum and copper using friction stir welding (FSW). The formation of intermetallic compounds at the weld interface hampers the weld quality. The use of an intermediate layer of a compatible material during welding reduces the formation of intermetallic compounds. The purpose of this paper is to optimize the FSW process parameters for AA6063-ETP copper weld, using a compatible zinc intermediate filler metal. Design/methodology/approach In the present study, a three-level, three-factor central composite design (CCD) has been used to determine the effect of various process parameters, namely, tool rotational speed, tool traverse speed and thickness of inter-filler zinc foil on ultimate tensile strength of the weld. A total of 60 experimental data were fitted in the CCD. The experiments were performed with tool rotational speeds of 1,000, 1,200 and 1,400 rpm each of them with tool traverse speeds of 5, 10 and 15 mm/min. A zinc inter-filler foil of 0.2 and 0.4 mm was also used. The macrograph of the weld surface under different process parameters and the tensile strength of the weld have been investigated. Findings The feasibility of joining 3 mm thick AA6063-ETP copper using zinc inter-filler is established. The regression analysis showed a good fit of the experimental data to the second-order polynomial model with a coefficient of determination (R2) value of 0.9759 and model F-value of 240.33. A good agreement between the prediction model and experimental findings validates the reliability of the developed model. The tool rotational speed, tool traverse speed and thickness of inter-filler zinc foil significantly affected the tensile strength of the weld. The optimal conditions found for the weld were, rotational speed of 1,212.83 rpm and traverse speed of 9.63 mm/min and zinc foil thickness is 0.157 mm; by using optimized values, ultimate tensile strength of 122.87 MPa was achieved, from the desirability function. Originality/value Aluminium and copper sheets could be joined feasibly using a zinc inter-filler. The maximum tensile strength of joints formed by inter-filler (122.87 MPa) was significantly better as compared to those without using inter-filler (83.78 MPa). The optimum process parameters to achieve maximum tensile strength were found by CCD.

scholarly journals Characteristics Study of Photovoltaic Thermal System with Emphasis on Energy Efficiency

2018 ◽  
Vol 152 ◽  
pp. 01003
Author(s):  
Chuah Yee Yong ◽  
Mohammad Taghi Hajibeigy ◽  
Chockalingam Aravind Vaithilingam ◽  
Rashmi Gangasa Walvekar
Keyword(s):  
Experimental Data ◽  
Energy Efficiency ◽  
Solar Energy ◽  
Thermal Energy ◽  
Heat Energy ◽  
Thermal System ◽  
Electrical Efficiency ◽  
Pv Panel ◽  
Photovoltaic Thermal System ◽  
Lower Temperature

Solar energy is typically collected through photovoltaic (PV) to generate electricity or through thermal collectors as heat energy, they are generally utilised separately. This project is done with the purpose of integrating the two systems to improve the energy efficiency. The idea of this photovoltaic-thermal (PVT) setup design is to simultaneously cool the PV panel so it can operate at a lower temperature thus higher electrical efficiency and also store the thermal energy. The experimental data shows that the PVT setup increased the electrical efficiency of the standard PV setup from 1.64% to 2.15%. The integration of the thermal collector also allowed 37.25% of solar energy to be stored as thermal energy. The standard PV setup harnessed only 1.64% of the solar energy, whereas the PVT setup achieved 39.4%. Different flowrates were tested to determine its effects on the PVT setup’s electrical and thermal efficiency. The various flowrate does not significantly impact the electrical efficiency since it did not significantly impact the cooling of the panel. The various flowrates resulted in fluctuating thermal efficiencies, the relation between the two is inconclusive in this project.

Body Force Modeling of the Aerodynamics of the Fan of a Turbofan at Windmill

2016 ◽  
Author(s):  
Guillaume Dufour ◽  
William Thollet
Keyword(s):  
Experimental Data ◽  
Rotational Speed ◽  
Body Force ◽  
Ground Level ◽  
Cost Ratio ◽  
Present Contribution ◽  
Force Modeling ◽  
Radial Profiles ◽  
Bypass Ratio ◽  
Good Agreement

The windmilling regime of a turbofan corresponds to a freewheeling mode of the fan rotor, driven by the ram pressure at the inlet. Early in the design process, determination of the windmilling rotational speed of the fan can be critical in the design of the supporting structure of the engine. Therefore, prediction of key parameters in windmilling is an important part of engine design. In particular, given the very high bypass ratio obtained at windmill (typically around 50), the flow in the fan stage and bypass duct is of prime interest, as it drives the establishment of the rotational speed of the low pressure spool and the overall drag. Classical CFD simulations have been shown to provide an adequate representation of the flow, but extensive parametric studies can be needed, which underlines the need for reduced-cost modeling of the flow in the engine. In this context, a body force modeling (BFM) approach to windmilling simulations is examined in the present contribution. The main objective is to assess the capability of the BFM approach to reproduce the aerodynamics of the flow in the fan rotor of a turbofan at windmill, and to propose a method to predict the rotational speed of the fan. The test case considered is a high-bypass ratio geared turbofan (the DGEN 380), which has been tested in an experimental facility designed to reproduce ground level windmilling conditions. The available global and local experimental data are used to validate the model. Furthermore, classical RANS simulations are also provided as reference simulations to assess the accuracy of the BFM results. It is found that the overall performance of the fan is well predicted by the BFM simulations, in particular at the low rotational regime associated to windmilling. In terms of local validation, radial profiles are also found to be in good agreement, except close to the shroud. Analysis of the CFD results shows this can be traced back to massive flow separation in the rotor tip area. In terms of cost, a BFM simulation is about 80 times faster than the baseline CFD computation, making this approach very efficient in term of accuracy-to-cost ratio. Finally, assuming zero-work exchange across the rotor, a transient equation for the rotational speed is derived and included in the time-marching process to the steady state. As a result, the rotational speed of the fan becomes an output of the simulations. The rotational speed predicted by the present model shows good agreement with engine experimental data. However, as only the rotor is modeled, the internal losses are not fully accounted for, and the massflow has to be specified from the experimental data. Further improvement of the approach will consist in modeling the stator and the complete secondary duct so that the loss, and therefore the massflow, can be predicted.

A new preset refueling mode for gasoline dispenser using frequency converter and flow rate signals

2016 ◽  
Vol 230 (6) ◽  
pp. 440-446
Author(s):  
Yajun Liu ◽  
J Cai ◽  
ZY Wang ◽  
ZY Huang
Keyword(s):  
Energy Efficiency ◽  
Flow Rate ◽  
Rotational Speed ◽  
Frequency Converter ◽  
Solenoid Valve ◽  
Measurement Transducer ◽  
Variable Speed ◽  
Service Station ◽  
Pumping System

Fuel dispenser is an integrated fuel pumping and metering system for automotive refueling at the service station. In this paper, we develop a preset refueling mode for the dispenser. A frequency converter and the flow rate signal from the measurement transducer are utilized instead of the solenoid valve, which is used to control the flow rate in the traditional refueling mode. With variable speed pumping system, the rotational speed of the pump is adjusted to achieve the desired flow rate and head necessary for the application. All the experiments were operated on a real dispenser system. How the frequency influences the refueling accuracy is observed. Through choosing a suitable frequency, not only accuracy but also energy efficiency improves compared with the traditional refueling mode. It is able to provide a reference for authority to fill in gaps in low-quantity (less than 5 L) refueling.

Effects of Pressure Ratio and Rotational Speed on Leakage Flow and Cavity Pressure in the Staggered Labyrinth Seal

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
Zhigang Li ◽  
Jun Li ◽  
Xin Yan ◽  
Zhenping Feng
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Rotational Speed ◽  
Stokes Equations ◽  
Pressure Ratio ◽  
Labyrinth Seal ◽  
Flow Coefficient ◽  
Leakage Flow ◽  
Cavity Pressure ◽  
Cavity Structure

Effects of pressure ratio and rotational speed on the leakage flow and cavity pressure characteristics of the rotating staggered labyrinth seal were investigated by means of experimental measurements and numerical simulations. The rotating seal test rig with turbine flowmeter and pressure measuring instruments was utilized to investigate the leakage flow of the staggered labyrinth seal at eight pressure ratios and five rotational speeds. The repeatability of the experimental data was demonstrated by three times measurements at different pressure ratios and fixed rotational speed. The three-dimensional Reynolds-averaged Navier–Stokes equations and standard k-ε turbulent model were also applied to study the leakage flow characteristics of the staggered labyrinth seal at the experimental conditions. The validation of the numerical approach was verified through comparison of the experimental data. The detailed flow field in the staggered labyrinth seal was illustrated according to the numerical simulations. The experimental and numerical results show that the leakage flow coefficient increases with increasing pressure ratio at the fixed rotational speed and is more sensitive to the smaller pressure ratio. The influence of rotational speed on the leakage flow coefficient is not obvious in the present rotational speed limitations. The cavity pressure coefficient in the staggered labyrinth seal decreases and is significantly influenced by the cavity structure along the flow direction.

scholarly journals RESEARCH OF ENERGY EFFICIENCY OF PROCESSING BY PULSE BARRIER DISCHARGE OF WATER IN A DROP-FILM STATE

2021 ◽  
Vol 2021 (3) ◽  
pp. 50-57
Author(s):  
V.O. Bereka ◽  
◽  
I.V. Bozhko ◽  
I.P. Kondratenko ◽  
◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Discharge Chamber ◽  
Barrier Discharge ◽  
Droplet Diameter ◽  
Model Solution ◽  
Organic Dye ◽  
Energy Yield ◽  
A Current ◽  
Model Water ◽  
Film State

The energy efficiency of a pulsed barrier discharge in air was investigated when it treated a model water sample in a drop-film state containing an organic dye (methylene blue) with an initial concentration of 50 mg/l. The water consumption was 4 l / min, the characteristic droplet diameter was ~1 mm. Water treatment was carried out in a coaxial discharge chamber with a gas gap of 3.2 mm and additionally in an ozonation chamber. The discharge was generated by short ~ 100 ns voltage pulses of ≈26 kV, which provided a current density with an amplitude of ≈1.3 A/cm2 and a pulse energy of ≈ 140 mJ. The time of decomposition of the impurity and the energy efficiency of the discharge were investigated as a function of the pulse repetition rate of 25−300 Hz. The discharge had the highest energy efficiency at frequencies of 25-50 Hz, at which the energy yield corresponding to 50% decomposition of the impurity is about 100 g/kW h. It is shown that most of ozone, one of the main oxidants generated by the discharge, dissolves in water in the discharge chamber. The concentration of ozone at the outlet from the discharge chamber can reach 2.2 mg/l. The remaining ozone is absorbed by the model solution (about 60%) in the ozonization chamber. References 16, figures 7.

scholarly journals POSSIBILITY OF UPDATING THE TURBO- COMPRESSOR PACKAGES OF GAS INDUSTRY BASED ON THE EFFICIENCY ANALYSIS RESULTS OF THEIR WORKING PROCESS

2018 ◽  
Vol 40 (1) ◽  
pp. 36-43
Author(s):  
I.N. Tertyshnyi ◽  
V.P. Parafejnik
Keyword(s):  
Experimental Data ◽  
Energy Efficiency ◽  
Gas Turbine ◽  
Efficiency Analysis ◽  
Working Process ◽  
Gas Industry ◽  
Turbine Engine ◽  
Increase Energy Efficiency ◽  
Turbo Compressor ◽  
System Characteristics

Using the experimental data on efficiency of centrifugal compressor and gas turbine engine being a part of the package GPA-C-6,3A the efficiency analysis of its working process is made. Based on it the package system characteristics and the recommendations to increase energy efficiency of gas turbine TCA are obtained.

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