High Efficient Metal Powder Production by Gas Atomisation Process

2007 ◽  
Vol 534-536 ◽  
pp. 57-60
Author(s):  
Rahmi Ünal ◽  
Mehmet Aydın
Keyword(s):  
Rate Ratio ◽  
Coupled System ◽  
Operating Conditions ◽  
Flow Rate Ratio ◽  
Powder Size ◽  
Nitrogen Gas ◽  
Fine Powders ◽  
High Efficient ◽  
The Mean ◽  
Mass Flow Rate Ratio

The most important parameter for production of fine powders efficiently is the velocity of the atomizing gas. This can be achieved by increasing the pressure, but this way will not be economic. For that reason, to achieve supersonic velocities different nozzle designs are used in close coupled configuration for an efficient atomization. In this study, a new laval type nozzle was designed and manufactured. Using this nozzle tin powder was produced in close coupled system by using nitrogen gas at different operating conditions. The results showed that the increasing the gas pressure up to 1.47 MPa reduced the mean powder size down to 11.39 microns with a gas/melt mass flow rate ratio of 2.0. Powders are spherical in shape and have smooth surfaces.

scholarly journals Aerodynamic Loss Increase due to Individual Film Cooling Injections From Gas Turbine Nozzle Surface

1998 ◽  
Author(s):  
Ryo Kubo ◽  
Fumio Otomo ◽  
Yoshitaka Fukuyama ◽  
Yuhji Nakata
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Loss ◽  
Rate Ratio ◽  
Flow Rate Ratio ◽  
Design Stage ◽  
Pressure Side ◽  
Mass Flow Rate Ratio

A CFD investigation was conducted on the total pressure loss variation for a linear nozzle guide vane cascade of a gas turbine, due to the individual film injections from the leading edge shower head, the suction surface, the pressure surface and the trailing edge slot. The results were compared with those of low speed wind tunnel experiments. A 2-D Navier-Stokes procedure for a 2-D slot injection, which approximated a row of discrete film holes, was performed to clarify the applicable limitation in the pressure loss prediction during an aerodynamic design stage, instead of a costly 3-D procedure for the row of discrete holes. In mass flow rate ratios of injection to main flow from 0% to 1%, the losses computed by the 2-D procedure agreed well with the experimental losses except for the pressure side injection cases. However, as the mass flow rate ratio was increased to 2.5%, the agreement became insufficient. The same tendency was observed in additional 3-D computations more closely modeling the injection hole shapes. The summations of both experimental and computed loss increases due to individual row injections were compared with both experimental and computed loss increases due to all-row injection with the mass flow rate ratio ranging from 0% to 7%. Each summation agreed well with each all-row injection result. Agreement between experimental and calculated results was acceptable. Therefore, the loss due to all-row injections in the design stage can be obtained by the correlations of 2-D calculated losses from individual row injections. To improve more precisely the summation prediction for the losses due to the present all-row injections, extensive research on the prediction for the losses due to the pressure side injection should be carried out.

scholarly journals Acidic Recovery from Wastewater of Automotive Battery Plant Using Membrane Technology

2016 ◽  
pp. 33-41
Author(s):  
Nantanee Chaimongkalayon ◽  
Sudtida P. Thanasupsin
Keyword(s):  
Flow Rate ◽  
Rate Ratio ◽  
Operating Conditions ◽  
Flow Rate Ratio ◽  
Anion Exchange Membranes ◽  
Recovery Efficiency ◽  
Optimum Flow Rate ◽  
Rate Ratios ◽  
Diffusion Dialysis ◽  
Acidic Wastewater

Diffusion dialysis (DD) equipped with anion exchange membranes (AEMs) is used as an effective tool to recover acidfrom various types of waste acid solutions. The aim of this study was to investigate the possibility of using the DD process to recover sulfuric acid (HsSO4) from the acidic wastewater from an automotive battery plant. A numbers of experimental runs was conducted to optimize the equipment’s operating conditions, particularly variations in feed flow and flow rate ratios . The results showed that H2SO4 permeated well through the AEM, while metal ions were efficiently rejected. The recovery of H2SO4 increased as flow rate decreased. Approximately 84.5% of H2SO4 could be recovered at 9 .38 × 10 -5 m3 h-1 m-2. Pb2+ rejection was 69.5%. In addition, recovery efficiency could be improved by increasing the flow rate ratio. At the highest flow rate ratio, DD could recover up to 90% of H2SO4 while the lowest rejection of Pb2+ (61%) was obtained. Also, the investigation of the effect of variation of flow rate ratio on recovery efficiency revealed that the optimum flow rate ratio should be controlled at around 1 to 1.2.

Influence of Physical Properties of Phases on Hydrodynamics and Mass Transfer Characteristics of a Liquid-Liquid Circular Microchannel

2016 ◽  
Author(s):  
Mehdi Sattari-Najafabadi ◽  
Bengt Sundén ◽  
Zan Wu ◽  
Mohsen Nasr Esfahany
Keyword(s):  
Mass Transfer ◽  
Physical Properties ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Rate Ratio ◽  
Operating Conditions ◽  
Flow Rate Ratio ◽  
Internal Diameter ◽  
Volumetric Mass Transfer Coefficient

The influences of operating conditions and physical properties of the two phases on the hydrodynamics and mass transfer in a circular liquid-liquid microchannel have been investigated. The polytetrafluoroethylene (PTFE) microchannel has an internal diameter of 0.7 mm and a T-shaped mixing junction. Sodium hydroxide solution was used as the aqueous phase. N-hexane and toluene were employed as the organic phases to investigate the effect of physical properties. Regarding the results, at constant total flow rate, raising the flow rate ratio enhanced the overall volumetric mass transfer coefficient. Using toluene as the organic solvent enhanced the overall volumetric mass transfer coefficient in average by 64.7% and 100.27% comparing to n-hexane-water at flow rate ratio of 1 and 0.5, respectively. This increment resulted in a decrement in the required mass transfer time and length in the microchannel. The length of the slugs had no considerable variation as n-hexane was replaced with toluene. Thus, the significant improvement of the overall volumetric mass transfer coefficient was because of the increment of the overall mass transfer coefficient, not the specific interfacial area.

Maximum Power Extraction From a Hot Stream in the Presence of Phase Change Under Limiting Collecting Temperatures

Volume 3 ◽  
2004 ◽  
Author(s):  
Juan C. Ordonez ◽  
Sheng Chen
Keyword(s):  
Phase Change ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rate Ratio ◽  
System Structure ◽  
Constructal Theory ◽  
Flow Rate Ratio ◽  
Power Extraction ◽  
Mass Flow Rate Ratio

In this paper we consider the fundamental problem of maximizing the power extraction from a hot stream when the collecting stream experiences a phase change and there are limits imposed by the materials on the operating temperatures. It constitutes an extension of [4] where it was pointed out the existence of an optimal mass flow rate ratio of the hot stream to the collecting stream. In this work, we study the effects of the restrictions imposed by limiting temperatures on the spatial configuration, power extraction and the optimal matching of the two streams. An optimal hot-stream-to-collecting-stream mass flow rate ratio can be found when the collecting stream experiences a phase change while in contact with the hottest section of the hot stream. Associated to the optimal mass flow rate ratio there is also an optimal heat exchanger area allocation. The effects of several operating parameters on the optimal configuration are documented. This paper constitutes an illustration of how thermodynamic optimization leads to the discovery of system structure (constructal theory [1]).

scholarly journals Controlling the thickness of hollow polymeric microspheres prepared by electrohydrodynamic atomization

2010 ◽  
Vol 7 (suppl_4) ◽  
Author(s):  
Ming-Wei Chang ◽  
Eleanor Stride ◽  
Mohan Edirisinghe
Keyword(s):  
Electron Microscopy ◽  
Rate Ratio ◽  
Shell Thickness ◽  
Polymer Concentration ◽  
Processing Parameters ◽  
Model Material ◽  
Hollow Microspheres ◽  
Flow Rate Ratio ◽  
Polymeric Microspheres ◽  
The Mean

In this study, the ability to control the shell thickness of hollow polymeric microspheres prepared using electrohydrodynamic processing at ambient temperature was investigated. Polymethylsilsesquioxane (PMSQ) was used as a model material for the microsphere shell encapsulating a core of liquid perfluorohexane (PFH). The microspheres were characterized by Fourier transform infrared spectroscopy and optical and electron microscopy, and the effects of the processing parameters (flow-rate ratio, polymer concentration and applied voltage) on the mean microsphere diameter ( D ) and shell thickness ( t ) were determined. It was found that the mean diameters of the hollow microspheres could be controlled in the range from 310 to 1000 nm while the corresponding mean shell thickness varied from 40 to 95 nm. The results indicate that the ratio D : t varied with polymer concentration, with the largest value of approximately 10 achieved with a solution containing 18 wt% of the polymer, while the smallest value (6.6) was obtained at 36 wt%. For polymer concentrations above 63 wt%, hollow microspheres could not be generated, but instead PMSQ fibres encapsulating PFH liquid were obtained.

scholarly journals Theoretical study on the influence of sprayed water temperature and minimum temperature difference to the efficiency of a humidification – dehumidification desalination unit

2016 ◽  
Vol 19 (2) ◽  
pp. 34-43
Author(s):  
Quoc Kien Vo ◽  
Hiep Chi Le ◽  
Tuyen Van Nguyen ◽  
Trinh Thi Minh Nguyen
Keyword(s):  
Heat Exchange ◽  
Water Temperature ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
Temperature Difference ◽  
Minimum Temperature ◽  
Rate Ratio ◽  
Theoretical Study ◽  
Flow Rate Ratio ◽  
Mass Flow Rate Ratio

The main content of the paper focuses on the theoretical study of the heat exchange between sprayed water and air in a humidification – dehumidification unit. The gained results [7] have been validated by using Hou data [1] and show that, in order to achieve the maximum GOR, the mass flow rate ratio between sprayed water and air depends on the sprayed water temperature and the minimum temperature difference ∆tmin. Particularly, the spayed water temperature should be from 70oC to 75oC when the minimum temperature difference ∆tmin= 5oC.

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