scholarly journals Visualization of hydrodynamic and physico-chemical processes in rotating and vibrating containers

2021 ◽  
Vol 2127 (1) ◽  
pp. 012004
Author(s):  
N V Kozlov ◽  
E A Mosheva ◽  
A V Shmyrov
Keyword(s):  
Video Recording ◽  
Experimental Studies ◽  
Laboratory System ◽  
Optical Instruments ◽  
Physico Chemical ◽  
Working Volume ◽  
Image Velocimetry ◽  
Hydrodynamic Processes ◽  
Fixed Phase ◽  
Hydrodynamic Systems

Abstract Variable inertial fields are an efficient way to control the behaviour of hydrodynamic systems. Forces of inertia can be used, for example, to stabilize or destabilize systems with an interface or density gradient, to mix multiphase or non-isothermal fluids. The implementation of this approach means that liquids fill the periodically moving containers. In this paper, the situations are considered when the containers perform either rotation or translational vibrations. Methods for measuring the density and velocity fields of convective flows in reacting hydrodynamic systems are described. Interferometry is used to visualize the density distribution. Particle image velocimetry (PIV) is used to study the structure and velocity of the flows. Optical instruments are installed stationary in the laboratory system. For video recording, a camera shutter is synchronized with the motion of a container, and thus the images are captured in a fixed phase of oscillations or rotation. Constructions of the containers make it possible to illuminate the working volume through transparent walls at different angles or in different planes. They also provide a compensation for the centrifugal pressure and allow interference cells to be used in overload conditions. The successful application of the methods in experimental studies of chemo-hydrodynamic processes is demonstrated.

Experimental Studies of the Primary Zone Flow Field and Combustion Performance of a Triple Swirler Combustor

2005 ◽  
Author(s):  
Yunhui Peng ◽  
Quanhong Xu ◽  
Yuzhen Lin
Keyword(s):  
Flow Field ◽  
Experimental Studies ◽  
Fuel Injector ◽  
Lean Blowout ◽  
Combustion Performance ◽  
Primary Zone ◽  
Image Velocimetry ◽  
Aero Engine ◽  
Exit Temperature ◽  
Promising Solution

Improvement of the lean blowout limit and more uniform combustor exit temperature distribution are particularly desirable for future aero engine. A triple swirler combination plus an airblast fuel injector might be a promising solution. The design with the triple swirler plus the airblast fuel injector including design A and B was presented and investigated in this paper. Single rectangle sector module combustor was used in the experiment for lean blowout (LBO), and three cups rectangle sector combustor was used for pattern factor (PF) experiments. The LBO and PF experiment data were provided. The primary zone flow field was measured by PIV (Particle Image Velocimetry) under atmospheric pressure and temperature. The result showed that the design A was a promising design, and the primary jet played very important role for flow field of primary zone. The insight relation between flow field and combustion performance could be found out from this paper.

scholarly journals Convection at an isothermal wall in an enclosure and establishment of stratification

2016 ◽  
Vol 799 ◽  
pp. 448-475 ◽  
Author(s):  
T. Caudwell ◽  
J.-B. Flór ◽  
M. E. Negretti
Keyword(s):  
Experimental Studies ◽  
Vertical Plane ◽  
Flow Characteristics ◽  
Similarity Solutions ◽  
Closed Cavity ◽  
Turbulent Transition ◽  
Image Velocimetry ◽  
Entrainment Coefficient ◽  
Isothermal Wall ◽  
Wall Plume

In this experimental–theoretical investigation, we consider a turbulent plume generated by an isothermal wall in a closed cavity and the formation of heat stratification in the interior. The buoyancy of the plume near the wall and the temperature stratification are measured across a vertical plane with the temperature laser induced fluorescence method, which is shown to be accurate and efficient (precision of $0.2\,^{\circ }$C) for experimental studies on convection. The simultaneous measurement of the velocity field with particle image velocimetry allows for the calculation of the flow characteristics such as the Richardson number and Reynolds stress. This enables us to give a refined description of the wall plume, as well as the circulation and evolution of the stratification in the interior. The wall plume is found to have an inner layer close to the heated boundary with a laminar transport of hardly mixed fluid which causes a relatively warm top layer and an outer layer with a transition from laminar to turbulent at a considerable height. The measured entrainment coefficient is found to be dramatically influenced by the increase in stratification of the ambient fluid. To model the flow, the entrainment model of Morton, Taylor & Turner (Proc. R. Soc. Lond. A, vol. 234 (1196), 1956, pp. 1–23) has first been adapted to the case of an isothermal wall. Differences due to their boundary condition of a constant buoyancy flux, modelled with salt by Cooper & Hunt (J. Fluid Mech., vol. 646, 2010, pp. 39–58), turn out to be small. Next, to include the laminar–turbulent transition of the boundary layer, a hybrid model is constructed which is based on the similarity solutions reported by Worster & Leitch (J. Fluid Mech., vol. 156, 1985, pp. 301–319) for the laminar part and the entrainment model for the turbulent part. Finally, the observed variation of the global entrainment coefficient, which is due to the increased presence of an upper stratified layer with a relatively low entrainment coefficient, is incorporated into both models. All models show reasonable agreement with experimental measurements for the volume, momentum and buoyancy fluxes as well as for the evolution of the stratification in the interior. In particular, the introduction of the variable entrainment coefficient improves all models significantly.

A membrane bioreactor for an innovative biological nitrogen removal process

2010 ◽  
Vol 61 (3) ◽  
pp. 671-676 ◽  
Author(s):  
W. Chen ◽  
F. Y. Sun ◽  
X. M. Wang ◽  
X. Y. Li
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Membrane Bioreactor ◽  
Loading Rate ◽  
Nitrogen Loading ◽  
Synthetic Wastewater ◽  
Biological Nitrogen Removal ◽  
Laboratory System ◽  
Working Volume ◽  
Biological Nitrogen

A hybrid system has been developed for biological nitrogen removal through nitrification-denitrification. The system includes an aerobic tank and an anoxic tank with an intermediate sludge settler connected to a membrane bioreactor (MBR) with a submerged 0.4 μm hollow-fiber membrane module. The laboratory system has a total working volume of 6.5 L treating a glucose-based synthetic wastewater. The experimental results demonstrate that the new process is highly effective for simultaneous organic and nitrogen removal. During the stationary operation, a sludge SS (suspended solids) concentration of 6 g/L or higher can be maintained in the reactors. The system has a COD (chemical oxygen demand) loading rate of up to 2,100 mg/L-d and a total nitrogen loading rate of up to 170 mg N/L-d. More than 95% COD can be degraded, and the total nitrogen removal efficiency can be 90% or higher as the nitrogen is reduced from 100 to around 7.5 mg/L. A high quality effluent is produced with a SS of less than 1 mg/L. With the MBR, organic degradation, nitrogen removal and sludge-liquid separation can be well achieved within a short HRT of about 10 hr.

scholarly journals The Effect Of Pow-Tega As Interactive Technique To Improve Students’ Speaking Ability At Senior High School Student

2021 ◽  
Vol 12 (4) ◽  
pp. 625-630
Author(s):  
Netty Huzniati Andas, Et. al.
Keyword(s):  
Classroom Environment ◽  
Test Score ◽  
Video Recording ◽  
Experimental Studies ◽  
Teaching Technique ◽  
Post Test ◽  
Speaking Skill ◽  
The Mean ◽  
Significant Stage ◽  
The Impact

Speaking is the art of conveying ideas and feelings by generating and sharing meaning through oral contact. Pow-Tega is a speaking skill teaching technique that combines a power teaching technique with a game to allow students to practice their speaking skills. Students' focus and excitement in speaking are developed using the power teaching technique. Students were inspired to study while playing the game because the classroom environment was more colorful. Researchers used a quantitative method by assigning pre-experimental studies with one group pre-test and post-test to determine the impact of the Pow-Tega technique on students' speaking performance. This study included 33 students as participants. The researchers used a spoken test and video recording to gather data. Before beginning treatment, researchers gave all of the samples a pre-test, then began treatment by using the Pow-Tega Technique for six meetings, and eventually, researchers gave all of the samples a post-test. The results revealed that the mean post-test score (3,93) was higher than the pre-test score (3,39). Furthermore, at the significant stage of 0,05 and degree of freedom -19, the ttest (6,75) was higher than the ttable (2.093). H0  has been  refused, while H1 has been accepted. That means there was a significant effect of students’ speaking ability after they were taught by using Pow-Tega.

scholarly journals Research of properties of traditional Carpathian cheeses

2019 ◽  
Vol 21 (91) ◽  
pp. 69-78 ◽  
Author(s):  
O. Y. Tsisaryk ◽  
I. M. Slyvka ◽  
L. Y. Musiy
Keyword(s):  
Staphylococcus Aureus ◽  
Salt Content ◽  
Experimental Studies ◽  
Enterobacter Aerogenes ◽  
Sour Milk ◽  
Physico Chemical ◽  
Staphylococcus Epidermis ◽  
Microbiological Parameters ◽  
Color Figure ◽  
Organoleptic Parameters

The purpose of the work was to investigate the organoleptic, physico-chemical and microbiological indices of traditional Carpathian cheeses, in particular, brynza, butz and vurda, made directly on the mountain valleys with traditional technology in Rakhiv district of the Transcarpathian region. Of 16 samples of cheese, 13 samples were cheese butz (samples 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15); vurda cheese (samples 4 and 16) and cheese of brynza a year ago (sample 14). Experimental studies of organoleptic, physico-chemical and microbiological parameters of cheese samples were carried out in the laboratory of the milk and milk products department and in the department of biotechnology at Rzeszow University (Poland). In samples of cheese, organoleptic parameters were studied in accordance with GOST 7616-85; active acidity – by potentiometric method using the pH meter of the ARN-9 brand; titrated acidity – titrarily (in degrees Turner) according to GOST 3624-67. The mass fraction of salt in the cheese was determined by titration of the extract with nitric oxide silver (GOST 3627-81). The detection of bacteria of the genus Staphylococcus aureus was determined by sowing on a solid Gissa with mannitol, with further detection and confirmation of the belonging of the grown colonies to Staphylococcus aureus (GOST 30347-97). The detection of bacteria of the genus Salmonella was determined by sowing on the Endo solid medium (GOST 31659-2012). The bacteria of the intestinal stem group were determined by sowing on a Kessler liquid medium (GOST 9225-84). Cultivation of microorganisms was carried out at temperature +37 °С for 48 h. According to researches of organoleptic parameters of cheeses it was found that samples of cheese butz were characterized by sour milk, and samples of 3 and 5 sour taste and aroma, a dense humus consistency and from gray to white color. Figure – with single small and large bodies of irregular shape. According to studies of organoleptic parameters of cheese, the taste and aroma of the product should be given – light sour milk, salted, which is confirmed by the salt content – 4.6%. Consistency was crumbly, the color was yellow. Samples of cheese vurda were characterized by delicate butter, sour milk taste and smell, paste, crumbly consistency and white color. Analyzing the acidity of butz cheese it was that it was high particularly in samples 3, 8 and 14, which was reflected in organoleptic parameters. In the samples of vurda titrated acidity was 75 °T in sample 4 (pH 5.7) and 16 °T in sample 16 (pH 6.4), while brynza was characterized by the highest acidity – 260 °T (pH 4.9). According to microbiological parameters, all specimens were characterized by the presence of pathogenic microflora. In particular, 1, 3, 5–9, 11–15 samples showed Staphylococcus aureus, 10 sample of Staphylococcus epidermis, 2 sample of bacteria of the genus Salmonella, 16 sample of Enterobacter aerogenes, and 4 samples of mold.

scholarly journals EXPERIMENTAL MODELING OF TSUNAMI BORE IMPINGEMENT ON A SIMPLIFIED COASTAL BUILDING

2018 ◽  
pp. 43
Author(s):  
Wei-Liang Chuang ◽  
Kuang-An Chang ◽  
James Kaihatu ◽  
Rodrigo Cienfuegos ◽  
Cyril Mokrani
Keyword(s):  
Tsunami Wave ◽  
Fluid Velocity ◽  
Experimental Studies ◽  
Wave Structure ◽  
Analytical Models ◽  
Comprehensive Investigation ◽  
Image Velocimetry ◽  
Sloping Beach ◽  
The Impact ◽  
Wave Structure Interaction

Numerous laboratory efforts were devoted to improve our understanding to the process of tsunami wave-structure interaction and provide valuable data to validate numerical and analytical models. However, the highly turbulent and multiphase nature of tsunami bores makes the study of their impacts very challenging. Many experimental studies (e.g., Shafiei et al. 2016) employed wave gauges to measure the bore height and estimate the bore front velocity based on shallow water equations. Considering the complexity of the flow and its impact with structures, the conversion between the bore height and the bore velocity is far from straightforward. Therefore, this study attempts to apply the bubble image velocimetry (BIV, Ryu et al. 2005) technique to directly measure the flow velocities during the tsunami bore impact. A tsunami wave, that breaks on a sloping beach, propagates inland as a form of bore, and impinges on a rigid structure, is considered as the scenario of interest. The objective is to perform a comprehensive investigation on the borestructure interaction by examining the fluid velocity, impact pressure, and surge force during the impact event with various structure headings.

scholarly journals Studies on Velocity Fields Around the Cavitation Vortices Generated by the Model of a Rotating Blade

2018 ◽  
Vol 25 (2) ◽  
pp. 66-70
Author(s):  
Witold Suchecki
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Velocity Fields ◽  
Process Equipment ◽  
Propeller Blade ◽  
Air Bubble ◽  
Rotating Blade ◽  
Hydraulic Machines ◽  
Image Velocimetry ◽  
Erosion Efficiency

Abstract The elimination of hazards caused by cavitation phenomena is an important issue to be considered in the design of process equipment including flow machinery. These hazards are: cavitation erosion, efficiency decrease as well as vibration and noise. One of the most intensive and dangerous forms of cavitation is vortex cavitation that accompanies the operation of hydraulic machines in which components comprised of rotating blades are applied. Velocity fields around cavitation vortices generated by the model of a propeller blade were experimentally studied in a cavitation tunnel. Flow images were recorded using a high-speed camera and processed using particle image velocimetry (PIV) complemented with computer-aided techniques that had been developed for the purpose of this research. These techniques included the removal of image distortions on the basis of a calibration mask, determination of instantaneous velocity distributions and removal of air-bubble traces from flow images. Experimental studies result examples were presented in the form of velocity fields determined in the longitudinal plane as well as in three transverse planes remote from the blade. Instabilities of the cavitating vortex stream and of the local liquid-flow velocity in its surrounding were detected. The effect of the angle of attack of propeller blade on the instability of the vortex stream and the effect of the presence of the cavitating vortex kernel on the local velocities of the surrounding liquid, were determined.

scholarly journals Experimental and numerical investigation on the convective thermal plume around the head of the standing and lying hu-man body

2019 ◽  
Vol 85 ◽  
pp. 02016 ◽  
Author(s):  
Laurenţiu Tăcutu ◽  
Ilinca Năstase ◽  
Florin Bode ◽  
Cristiana Verona Croitoru ◽  
Angel Dogeanu ◽  
...  
Keyword(s):  
Distribution System ◽  
Particle Image ◽  
Numerical Models ◽  
Experimental Studies ◽  
Air Distribution ◽  
Thermal Plume ◽  
Thermal Plumes ◽  
Image Velocimetry ◽  
Convective Thermal ◽  
Made In

This paper presents a study for two thermal plumes generated by two humanoid thermal manikins, one standing and one lying down. The research was approached from a numerical and experimental perspective. The numerical model represents an operating room (OR) with two surgeons, a patient and a unidirectional air flow (UAF) diffuser. The experimental study was made in a climatic chamber, having a similar air distribution system, using particle image velocimetry (PIV) and infrared thermography (IR) measurements. The purpose of the study was to characterize the thermal plumes of the two manikins by numerical and experimental studies. The results obtained from these different approaches were compared with each other and with the ones from the literature in order to validate our numerical models.

Biological Features of Tumors Results of Experimental Studies

2017 ◽  
Vol 68 (3) ◽  
pp. 594-598
Author(s):  
Ana Camelia Grigore ◽  
Camelia Busila ◽  
Ioana Bianca Chesaru ◽  
Alina Calin ◽  
Liliana Lacramioara Pavel
Keyword(s):  
Structural Changes ◽  
Malignant Tumors ◽  
Experimental Studies ◽  
Subsequent Development ◽  
Entire Body ◽  
Tumor Transplantation ◽  
Physico Chemical ◽  
Long Time ◽  
Level Of Knowledge ◽  
Aseptic Conditions

Tumor anaplasia can be of varying degrees, being especially marked in fast-growing malignant tumors. Blastomatose tissue is characterized by morphological, chemical, physico-chemical and energetic anaplasia. Structural changes of the tissue specific to blastomatose growth often provide the opportunity to differentiate this tissue from a normal or any other growing tissue. Out of various factors that may influence the external environment of tumors, we should mention food, profession, living and working conditions. Tumors and especially malignant tumors are accompanied by changes in the entire body. These are not just a consequence of the blastomatose growth but also play a role in its subsequent development. Experimental tumors are one of the methods of studying the issue of blastomatose growth. The tumor transplantation method is widespread and extensively applied in laboratory practice. It uses standard strains of tumors (rats, mice, etc.). The simplicity of the tumor transplantation method, which consists of the inoculation under the skin of animals of tumor fragments using a trocar or of the injection of a tumor emulsion under aseptic conditions, enables researchers to maintain the purity of the strain for a long time. Various views have been formulated at different times on the origin of tumor growth in accordance with the level of knowledge on this issue.

Results of experimental studies of integrated physico-chemical impact in carbonate reservoirs

2021 ◽  
pp. 34-39
Author(s):  
R.U. Rabaev ◽  
◽  
Sh.Kh. Sultanov ◽  
V.E. Andreev ◽  
A.V. Chibisov ◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Reaction Rate ◽  
Experimental Studies ◽  
Dissolution Kinetics ◽  
Carbonate Reservoirs ◽  
Reservoir Rock ◽  
Highly Active ◽  
Physico Chemical ◽  
Acid Reaction ◽  
Dissolution Efficiency

The article highlights the experimental studies results of carbonate rock dissolution kinetics in order to develop effective methods of slowing down the acid reaction rate in the heterogeneous structures. It was found that the intensity of carbonate reservoirs leaching process with the addition of hydrocarbon solvents such as dioxanes increases due to the acetals transition to the oil phase, dissolution of highly active oil components and more intense penetration of an aqueous solution of hydrochloric acid to the carbonate matrix of the reservoir rock, which intensifies the process of leaching. The technology of complex physico-chemical impact on carbonate reservoirs has been developed. It is shown that the use of a aqueous hydrochloric acid solutions mixture and an organic solvent leads to an increase in the dissolution efficiency to 88% and the reaction rate increases by a factor of 3.5.

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