Experimental Study on Effects of Slot Hot Blowing on Secondary Water Droplet Size and Water Film Thickness

2008 ◽  
Author(s):  
Chunguo Li ◽  
Xinjun Wang ◽  
Daijing Cheng ◽  
Bi Sun
Keyword(s):  
Droplet Size ◽  
Water Droplet ◽  
Pressure Difference ◽  
Water Film ◽  
Droplet Size Distribution ◽  
Experimental Tests ◽  
Suction Side ◽  
Maximum Diameter ◽  
Water Droplets ◽  
Water Separation

The effects of the slot hot blowing of the hollow stator blades on the size of secondary water droplets and the thickness of the water film were experimentally investigated in this paper. The experiment was carried out on the turbine blade cascades in a wet air tunnel with an inlet air wetness fraction of 7.9%, an outlet air velocity of 170m/s, a slot width of 1.0mm and a slot angle of 45° to blade surface. The Malvern Droplet and Particle Size Analyser was utilized to measure the secondary water droplet size and distribution downstream of the hollow stator blades in the experimental tests. The experimental results show that the maximum diameter and Sauter mean diameter of the secondary water droplets were reduced greatly and the water droplet size distribution became narrower. The larger blowing pressure difference resulted in the smaller secondary water droplets and the narrower water droplet size distributions. In addition, the efficiency of water separation from the hollow stator blade surfaces was higher for slot on the suction side than that of the pressure side case. Another simplified experimental test was also carried out on the flat plate to investigate the effect of slot hot blowing on the thickness of the water film downstream of the slot. The conductivity probes were used to measure the thickness of the water film downstream and upstream of the blowing slot. The results show that the slot hot blowing reduced the thickness of the water film downstream of the slot, which was affected by the blowing pressure difference and temperature difference between the hot blowing air and the main airflow. In conclusion, the slot hot blowing of the hollow stator blades has reduced the size of the secondary water droplets and secondarily has evaporated a little water film on the blade surfaces. Both effects are beneficial to reduce the erosion damage to the rotor blades.

Experimental Study on Effects of Slot Hot Blowing on Secondary Water Droplet Size and Water Film Thickness

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Chunguo Li ◽  
Xinjun Wang ◽  
Daijing Cheng ◽  
Bi Sun
Keyword(s):  
Droplet Size ◽  
Water Droplet ◽  
Pressure Difference ◽  
Water Film ◽  
Droplet Size Distribution ◽  
Experimental Tests ◽  
Suction Side ◽  
Maximum Diameter ◽  
Water Droplets ◽  
Water Separation

The effects of the slot hot blowing of the hollow stator blades on the size of secondary water droplets and the thickness of the water film were experimentally investigated in this paper. The experiment was carried out on the turbine blade cascades in a wet air tunnel with an inlet air wetness fraction of 7.9%, an outlet air velocity of 170 m/s, a slot width of 1.0 mm, and a slot angle of 45 deg to blade surface. The Malvern droplet and particle size analyzer was utilized to measure the secondary water droplet size and distribution downstream of the hollow stator blades in the experimental tests. The experimental results show that the maximum diameter and Sauter mean diameter of the secondary water droplets were reduced greatly, and the water droplet size distribution became narrower. The larger blowing pressure difference resulted in the smaller secondary water droplets and the narrower water droplet size distributions. In addition, the efficiency of water separation from the hollow stator blade surfaces was higher for slot on the suction side than that of the pressure side case. Another simplified experimental test was also carried out on the flat plate to investigate the effect of slot hot blowing on the thickness of the water film downstream of the slot. The conductivity probes were used to measure the thickness of the water film downstream and upstream of the blowing slot. The results show that the slot hot blowing reduced the thickness of the water film downstream of the slot, which was affected by the blowing pressure difference and temperature difference between the hot blowing air and the main airflow. In conclusion, the slot hot blowing of the hollow stator blades has reduced the size of the secondary water droplets and secondarily has evaporated a little water film on the blade surfaces. Both effects are beneficial to reduce the erosion damage to the rotor blades.

scholarly journals Water droplet calibration of the Cloud Droplet Probe (CDP) and in-flight performance in liquid, ice and mixed-phase clouds during ARCPAC

2010 ◽  
Vol 3 (6) ◽  
pp. 1683-1706 ◽  
Author(s):  
S. Lance ◽  
C. A. Brock ◽  
D. Rogers ◽  
J. A. Gordon
Keyword(s):  
Laser Beam ◽  
Droplet Size ◽  
Liquid Water ◽  
Water Droplet ◽  
Optical Design ◽  
Cloud Droplet ◽  
Mixed Phase ◽  
Water Droplets ◽  
Sample Area ◽  
Mixed Phase Clouds

Abstract. Laboratory calibrations of the Cloud Droplet Probe (CDP) sample area and droplet sizing are performed using water droplets of known size, generated at a known rate. Although calibrations with PSL and glass beads were consistent with theoretical instrument response, liquid water droplet calibrations were not, and necessitated a 2 μm shift in the manufacturer's calibration. We show that much of this response shift may be attributable to a misalignment of the optics relative to the axis of the laser beam. Comparison with an independent measure of liquid water content (LWC) during in-flight operation suggests much greater biases in the droplet size and/or droplet concentration measured by the CDP than would be expected based on the laboratory calibrations. Since the bias in CDP-LWC is strongly concentration dependent, we hypothesize that this discrepancy is a result of coincidence, when two or more droplets pass through the CDP laser beam within a very short time. The coincidence error, most frequently resulting from the passage of one droplet outside and one inside the instrument sample area at the same time, is evaluated in terms of an "extended sample area" (SAE), the area in which individual droplets can affect the sizing detector without necessarily registering on the qualifier. SAE is calibrated with standardized water droplets, and used in a Monte-Carlo simulation to estimate the effect of coincidence on the measured droplet size distributions. The simulations show that extended coincidence errors are important for the CDP at droplet concentrations even as low as 200 cm−3, and these errors are necessary to explain the trend between calculated and measured LWC observed in liquid and mixed-phase clouds during the Aerosol, Radiation and Cloud Processes Affecting Arctic Climate (ARCPAC) study. We estimate from the simulations that 60% oversizing error and 50% undercounting error can occur at droplet concentrations exceeding 400 cm−3. Modification of the optical design of the CDP is currently being explored in an effort to reduce this coincidence bias.

A water droplet size distribution dependent modeling of hydrate formation in water/oil emulsion

AIChE Journal ◽  
2016 ◽  
Vol 63 (3) ◽  
pp. 1010-1023 ◽  
Author(s):  
Yi-Ning Lv ◽  
Chang-Yu Sun ◽  
Bei Liu ◽  
Guang-Jin Chen ◽  
Jing Gong
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Water Droplet ◽  
Hydrate Formation ◽  
Droplet Size Distribution ◽  
Oil Emulsion

scholarly journals Experimental Study on the Performance of a Novel Compact Electrostatic Coalescer with Helical Electrodes

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1733
Author(s):  
Yi Shi ◽  
Jiaqing Chen ◽  
Zehao Pan
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Water Content ◽  
Water Droplet ◽  
Separation Process ◽  
Water Droplets ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water

As most of the light and easy oil fields have been produced or are nearing their end-life, the emulsion stability is enhanced and water cut is increasing in produced fluid which have brought challenges to oil–water separation in onshore and offshore production trains. The conventional solution to these challenges includes a combination of higher chemical dosages, larger vessels and more separation stages, which often demands increased energy consumption, higher operating costs and larger space for the production facility. It is not always feasible to address the issues by conventional means, especially for the separation process on offshore platforms. Electrostatic coalescence is an effective method to achieve demulsification and accelerate the oil–water separation process. In this paper, a novel compact electrostatic coalescer with helical electrodes was developed and its performance on treatment of water-in-oil emulsions was investigated by experiments. Focused beam reflectance measurement (FBRM) was used to make real-time online measurements of water droplet sizes in the emulsion. The average water droplet diameters and number of droplets within a certain size range are set as indicators for evaluating the effect of coalescence. We investigated the effect of electric field strength, frequency, water content and fluid velocity on the performance of coalescence. The experimental results showed that increasing the electric field strength could obviously contribute to the growth of small water droplets and coalescence. The extreme value of electric field strength achieved in the high-frequency electric field was much higher than that in the power-frequency (50 Hz) electric field, which can better promote the growth of water droplets. The initial average diameters of water droplets increase with higher water content. The rate of increment in the electric field was also increased. Its performance was compared with that of the plate electrodes to further verify the advantages of enhancing electrostatic coalescence and demulsification with helical electrodes. The research results can provide guidance for the optimization and performance improvement of a compact electrocoalescer.

scholarly journals Demulsification of Water in Iraqi Crude Oil Emulsion

2019 ◽  
Vol 25 (11) ◽  
pp. 37-46
Author(s):  
Zenah Hani Maddah ◽  
Tariq Mohammed Naife
Keyword(s):  
Crude Oil ◽  
Water Content ◽  
Droplet Size ◽  
Water Droplet ◽  
Salt Content ◽  
Droplet Size Distribution ◽  
Oil Emulsion ◽  
Separation Rate ◽  
Average Water ◽  
Oil Emulsions

Formation of emulsions during oil production is a costly problem, and decreased water content in emulsions leads to increases productivity and reduces the potential for pipeline corrosion and equipment used. The chemical demulsification process of crude oil emulsions is one of the methods used for reducing water content. The demulsifier presence causes the film layer between water droplets and the crude oil emulsion that to become unstable, leading to the accelerated of water coalescence. This research was performed to study the performance of a chemical demulsifier Chimec2439 (commercial) a blend of non-ionic oil-soluble surfactants. The crude oils used in these experiments were Basrah and Kirkuk Iraqi crude oil. These experimental work were done using different water to oil ratio. The study investigated the factors that have a role in demulsification processes such as the concentration of demulsifier, water content, salinity, pH, and asphaltene content. The results showed in measuring the droplet size distribution, in Basrah crude oil, that the average water droplet size was between (5.5–7.5) μm in the water content 25% while was between (3.3-4) μm in the water content 7%. The average water droplet size depends on the water content, and droplet size reduced when the water content of emulsion was less than 25%. In Kirkuk crude oil, in water content of 7%, it was between (4.5-6) μm, while in 20%, it was between (4-8) μm, and in 25% it was between (5-8.8) μm. It was found that the rate of separation increases with increasing concentration of demulsifier. For Basrah crude oil at 400ppm the separation was 83%, and for Kirkuk, crude oil was 88%. The separation of water efficiency was increased with increased water content and salt content. In Basrah crude oil, the separation rate was 84% at a dose of salt of 3% (30000) ppm and at zero% of salt, the separation was70.7%. In Kirkuk crude oil, the separation rate was equal 86.2% at a dose of salt equal 3% (30000) ppm, and at zero% of salt, the separation 80%.  

Adaptation of Test Methodology and the Evolution of a Demulsifier Formulation for a Heavy Oil Start-Up

2021 ◽  
Author(s):  
A. White ◽  
R. Miller ◽  
E. Bellu ◽  
J. J. Wylde
Keyword(s):  
Water Quality ◽  
Crude Oil ◽  
Droplet Size ◽  
Water Droplet ◽  
Base Case ◽  
High Shear ◽  
Screening Process ◽  
Interface Quality ◽  
Water Separation ◽  
Optimum Result

Abstract Objectives/Scope Selection of "first fill" demulsifiers for new, undeveloped, oil fields has significant limitations, typically relying on data from test work with synthetic emulsion created in a laboratory using highly contaminated drilling samples of crude oil. Additional separation challenges related to offshore production of high viscosity, low API crude oil, from a low temperature reservoir results in a low probability of success in selecting a suitable first fill demulsifier using the traditional bottle test alone. Methods, Procedures, Process To give improved speed of oil/water separation, water quality, interface quality and top oil dehydration, samples of chemical free oil and produced water were used to screen alternative existing products against the base case demulsifier via bottle testing. The emulsions were created using a high shear stirrer to mimic the system conditions of the wells coming online and water droplet size within the emulsion was determined via cross polarizing thermal microscopy. For the purposes of these tests, demulsifier performance was ranked on speed and completeness of separation, interface quality, water quality and grind out (BS&W) characteristics. Results, Observations, Conclusions Several differences were observed between the initial and subsequent test work. The low shear emulsion created in the early work was found to be very unstable, separating easily with no residual emulsion in the crude oil. The emulsion created under high shear conditions gave a much closer correlation in terms of water droplet distribution to that measured during the field test and resulted in a much more stable emulsion that was more difficult to separate and typically left unresolved emulsion in the oil after the bulk of the water had separated. Whilst the original demulsifier recommendation was still able to facilitate separation it was found that it was no longer the optimum product, with other previously disregarded products able to provide a higher level of performance on the high shear emulsion. Novel/Additive Information This paper demonstrates that a higher level of performance was achieved with an enhanced screening process, namely through high shear stirring and confirmation of water droplet size within the emulsion. When added to the standard bottle testing conditions, the development of demulsifiers can better ensure an optimum result, fit for purpose for the application.

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