flow rates
Recently Published Documents


TOTAL DOCUMENTS

6250
(FIVE YEARS 1833)

H-INDEX

86
(FIVE YEARS 17)

Author(s):  
Gabriel G. Zimmermann ◽  
Samir P. Jasper ◽  
Daniel Savi ◽  
Leonardo L. Kmiecik ◽  
Lauro Strapasson Neto ◽  
...  

ABSTRACT The establishment of grain crops in Brazil is an important industrial process in the agricultural chain, requiring the correct deposition of granular fertilizer over the sowing furrow and more efficient, precise, and sustainable assessments in the operation, which can be achieved with the statistical process control. This study aimed to assess the effect of the angular velocity on different inclinations of the helical metering mechanism on the granular fertilizer deposition. An automated electronic bench was used to assess the deposition quality of granular fertilizers considering different angular velocities (1.11, 1.94, and 2.77 m s-1) and longitudinal and transverse inclinations (+15, +7.5, 0, −7.5, and −15°), with the helical doser by overflow. Flow data were collected and submitted to descriptive statistics and statistical process control. The metering mechanism showed expected variations, with acceptable performance under process control. The values of the flow rates of the granular fertilizer increased as velocity increased, standing out longitudinal inclinations of +7.5 and +15°, providing higher fertilizer depositions.


2022 ◽  
Vol 56 ◽  
pp. 101862
Author(s):  
J. Arturo Mendoza-Nieto ◽  
Héctor Martínez-Hernández ◽  
Heriberto Pfeiffer ◽  
J. Francisco Gómez-García
Keyword(s):  

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 583
Author(s):  
Suleyman Emre Ak ◽  
Sertac Cadirci

In this study, the effect of suction flow control on a centrifugal compressor at operation and stall flow rates was investigated using computational fluid dynamics (CFD). The compressor geometry was reconstructed from available open source profile data and the CFD analyses have been performed on this geometry using the appropriate mesh. To validate the CFD results, the compressor performance line was acquired and compared with the experimental results obtained at the design rotational speed. Then, suction flow control was employed at various suction slot positions with different suction flow rates to improve the performance of the compressor at operation and stall flow rates. As a result of the suction flow control trials, 0.85% increase in pressure ratio and 0.8% increase in adiabatic efficiency were achieved while the compressor was running at operation flow rate. The performance improvements corresponding to the stall flow rate of the compressor were 2.5% increase in pressure ratio and 2% increase in adiabatic efficiency.


2022 ◽  
Vol 14 (2) ◽  
pp. 835
Author(s):  
Hafiz Muhammad Habib ◽  
Hafiz Muhammad Ali ◽  
Muhammad Usman

Condensers are an integral part of air conditioning systems. The thermal efficiency of condensers solely depends on the rate of heat transfer from the cooling medium. Fin tubes are extensively used for heat transfer applications due to their enhanced heat transfer capabilities. Fins provide appreciable drainage because surface tension produces pressure gradients. Much research, contributed by several scientists, has focused on adjusting parameters, such as fin design, flow rates and retention angles. In this study, a setup with an observing hole was used to inspect the influence on retention angle of adjusting the flow rates of the fluid. The increase in retention angle was examined using several velocities and concentration mixtures. Pin-fin tubes were used to obtain coherent results using a photographic method. The experimental setup was designed to monitor the movement of fluid through the apparatus. The velocity was varied using dampers and visibility was enhanced using dyes. Photographs were taken at 20 m/s velocities after every 20 s. and 0.1% concentration and the flooding point observed. The experimental results were verified by standard observation which showed little variation at lower velocity. For water/water-propanol mixtures, a vapor velocity of 12 m/s and concentration ratio of 0.04% was the optimal combination to achieve useful improvement in retention angle. With increase of propanol from 0% to 0.04%, the increase in retention angle was greater compared to 0.04% to 0.1%. For velocities ranging from 0 to 12 m/s, the increase in retention angle was significant. A sharp change was observed for concentration ratios ranging from 0.01% to 0.05% compared to 0.05% to 0.1%.


2022 ◽  
Author(s):  
Norah Aljuryyed ◽  
Abdullah Al Moajil ◽  
Sinan Caliskan ◽  
Saeed Alghamdi

Abstract Acid retardation through emulsification is commonly used in reservoir stimulation operations, however, emulsified acid are viscous fluids, thus require additional equipment at field for preparation and pumping requirements. Mixture of HCl with organic acids and/or chemical retarders have been used developed to retard acid reaction with carbonate, however, lower dissolving power. Development of low viscosity and high dissolving retarded acid recipes (e.g., equivalent to 15-26 wt.% HCl) addresses the drawbacks of emulsified acids and HCl acid mixtures with weaker organic acids. The objective of this study is to compare wormhole profile generated as a result of injecting acids in Indian limestone cores using 28 wt.% emulsified acid and single-phase retarded acids at comparable dissolving power at 200 and 300°F. Coreflood analysis testing was conducted using Indiana limestone core plugs to assess the pore volume profile of retarded acid at temperatures of 200 and 300° F. This test is supported by Computed Tomography to evaluate the propagation behavior as a result of the fluid/rock reaction. Wider wormholes were observed with 28 wt.% emulsified acid at 200°F when compared to test results conducted at 300°F. The optimum injection rate was 1 cm3/min at 200 and 300°F based on wormhole profile and examined flow rates. Generally, face-dissolution and wider wormholes were observed with emulsified acids, especially at 200°F. Narrower wormholes were formed as a result of injecting retarded acids into Indiana limestone cores compared to 28 wt.% emulsified acid. Breakthrough was not achieved with retarded acid recipe at 300°F and flow rates of 1 and 3 cm3/min, suggesting higher flow rates (e.g., > 3 cm3/min) are required for the retarded acid to be more effective at 300°F.


2022 ◽  
Vol 20 (4) ◽  
pp. 95-100
Author(s):  
M. V. Chubarnova ◽  
A. B. Davydov ◽  
V. A. Esin ◽  
O. B. Davydova ◽  
I. O. Kostin

Introduction. The outbreak of a new coronavirus infection has become a challenge for the global health system. The COVID-19 infection is directly related to various disorders of the cardiovascular system, including the microcirculatory bed, caused by thrombotic events and deteriorations of blood rheology. Aims. The paper reports on the results of a study of Doppler sonographic parameters changes in patients with a novel coronavirus infection over the past 6 months. Materials and methods. We assessed the oral mucosa microcirculation in three segments using the high-frequency ultrasound dopple-rography. Results. We recorded the linear and volumetric blood flow rates and the Gosling and Purselo indexes in the course of our work. When comparing the obtained average statistical parameters of blood flow velocity, the linear and volumetric blood flow rates in patients of both groups were found to be lain in the same range and the mean values of Vas, Vam, Qas were equal. The mean values of the Purselo resistance index were closer to 1,0 in patients with COVID-19, and the values of the Gosling pulsation index (PI) were on average 53.3 % higher than in the control group. Conclusion. We evaluated the screening capabilities and potential of high-frequency ultrasound dopplerography for use in patients of different age groups and different somatic status.


Soil Systems ◽  
2022 ◽  
Vol 6 (1) ◽  
pp. 6
Author(s):  
Chad J. Penn ◽  
Mark R. Williams ◽  
James Camberato ◽  
Nicholas Wenos ◽  
Hope Wason

Soil phosphorus (P) solubility and kinetics partly control dissolved P losses to surface water and uptake by plants. While previous studies have focused on batch techniques for measuring soil P desorption kinetics, flow-through techniques are more realistic because they simulate P removal from the system, akin to runoff, leaching, and plant uptake. The objectives were to measure soil P desorption by a flow-through technique at two flow rates and several batch methods, and utilize both for understanding how flow rate impacts the thermodynamics and kinetics of soil P desorption. Desorption obeyed first-order kinetics in two different phases: an initial rapid desorption phase followed by a gradual release. Desorption was limited by equilibrium and the kinetics of physical processes as demonstrated by an interruption test. Dilution-promoted desorption occurred with increasing cumulative volume, which increased desorption rate via first-order kinetics. The batch tests that simulated cumulative solution volume and time of flow-through were similar to the flow-through results; however, the batch methods overestimated the desorption rates due to less limitations to diffusion. Fast flow rates desorbed less P, but at a greater speed than slow flow rates. The differences were due to contact time, cumulative time, and solution volume, which ultimately controlled the potential for chemical reactions to be realized through physical processes. The interaction between these processes will control the quantity and rate of desorption that buffer P in non-point drainage losses and plant uptake.


Author(s):  
Juliana H. Giffoni ◽  
Raffaella B. C. Teixeira ◽  
Raphael R. Wenceslau ◽  
Melina A. F. Abrantes ◽  
Jéssica G. Oliveira ◽  
...  

2022 ◽  
pp. 1-10
Author(s):  
Serdar Hicdurmaz ◽  
Reiner Buck ◽  
Bernhard Hoffschmidt

Abstract Particle solar receivers promise economical and operational advantages compared to the molten salt based solar receivers. In this study, an experiment is designed to observe the particle flow characteristics in the Centrifugal Solar Particle Receiver. A set of experiments for various receiver rotation speeds and particle mass flow rates is conducted, and experimentally obtained raw results are post-processed by means of an Image Processing Routine based on 4BestEstimate algorithm[1]. The axial advance of the particles in one turn, the particle film thickness and the ratio of the stationary zone to the receiver circumference are measured in order to be later used in the validation study of the Discrete Element Method based numerical model.


Sign in / Sign up

Export Citation Format

Share Document