Decrease In Hydraulic Resistance Research Articles

Investigation of hydraulic resistance of pulsating flows of viscous fluid in elastic pipe

In recent years, flexible pipes made of synthetic polymer materials are being rapidly introduced into practice. Pulsating currents are important in driving water and other liquids in main pipes. This paper examines the pulsating currents of a viscous incompressible fluid in an elastic pipe. The necessary hydrodynamic parameters will be determined by solving the problem, such as distributions of pressure, velocity, flow rate, propagation velocity of the pressure pulse wave, and their attenuation. For the first time in this article, the decrease in hydraulic resistance in a pulsating flow through pipes due to the elasticity of the wall will be determined. The dependence of the dimensionless value of the pressure pulse wave on the vibrational numberαis studied. The pulse wave speed is compared with the speed of Moens-Korteweg, c∞and significant differences between them are found. The dependence of the reciprocal value of attenuation, related to the wavelength, on the vibrational numberαis also studied; it is shown that the attenuation is free at lower values of the Womersley vibrational parameter, practically equals zero, and at large values of which it asymptotically approaches unity [1-9].

Study of the Hydraulic Resistance and Heat and Mass Transfer Characteristics of Prismatic Packing for Various Options of Its Installation

The results of experimental studies of hydraulic resistance, heat and mass transfer characteristics of a prismatic lattice polymer regular packing for various options of its installation in space are presented. Based on the conducted experimental studies, the most rational design of packing installation was determined (taking into account the decrease in hydraulic resistance and the increase in the efficiency of heat and mass transfer processes), for which the geometric characteristics are given and empirical dependences are obtained, which make it possible to determine the value of the hydraulic resistance of the dry and irrigated packing, the values of the volumetric coefficients of mass transfer and heat transfer. The results of the study can be used in enterprises where different types of cooling towers or devices for conducting heat and (or) mass transfer processes, such as absorption, are used, as well as in the development of packed scrubbers.

Pulsing Flows of a Viscous Incompressible Liquid in a Pipe with Elastic Walls

As you know, the recent intensive introduction into practice of flexible pipelines made of polymer synthetic materials, pulsating fluid flow in elastic pipes is of great importance. As you know, the recent intensive introduction into practice of flexible pipelines made of polymer synthetic materials, pulsating fluid flow in elastic pipes is of great importance. By solving the problem, the necessary hydrodynamic parameters will be determined, such as pressure distributions, velocities, flow rates, the speed of propagation of the pulse wave pressure and their decay. For the first time in this article, a decrease in hydraulic resistance in a pulsating flow through pipes due to the elasticity of the wall will be determined. The dependence of the dimensionless value of the pressure pulse wave on the vibrational number was investigated .The speed of the pulse wave was compared with the speed of Moens-Korteweg , and significant differences were revealed between them occurring at lower values of the Womersley oscillatory parameter, at large values of which significant differences are not observed. The dependence of the reciprocal damping per wavelength on the vibrational number , was also investigated; it was shown that the damping is free at smaller values of the Womersley vibrational parameter, practically equal to zero, and at large values of which it asymptotically approaches unity.

Improving the energy efficiency of cyclone dust collectors

Our study, aimed at assessing the impact exerted by the inclusion to a low-efficiency cyclone of an additional "bypass" pipe connecting the cyclone's inlet branch pipe and the exhaust pipe, has been established the mechanisms to improve the energy efficiency and the process of purifying air from dust. It has been proven that the increase in the degree of purification is explained by a decrease in the radial flow rate under the exhaust pipe of the cyclone. The decrease in hydraulic resistance is due to a decrease in the flow rate along the inlet branch pipe when the air is fed separately to the body through the inlet branch pipe and the "bypass" pipe. Our experimental study has confirmed that when the cyclone design is supplemented with a "bypass" pipe in the most dangerous area of the cyclone in terms of dust release (under the exhaust pipe), the radial rate of the gas flow that negatively affects purification is reduced. This leads to an increase in the overall degree of purification from dust. The result of analytical calculations and computer simulation by the SolidWorks-2009 software were experimentally confirmed when investigating the effectiveness of dust capture from powdered skimmed milk in an industrial cyclone (a 630-mm diameter) with a "bypass" pipe. Such a cyclone is installed in the system of pneumatical transportation at the spray dryer "CT-500" at Ichnya Milk Powder and Butter Plant (Ukraine). Specifically, it has been established that the removal of dust is reduced almost twice, hydraulic resistance ‒ by 15 %, and the energy efficiency of the cyclone with a "bypass" pipe increases by 2.43 times.Thus, there is a reason to argue about the possibility of significant energy efficiency improvement of the cyclone with a "bypass" pipe.This makes it possible to assess the energy efficiency of the cyclone in the early stages of design

К ВОПРОСУ О СКОРОСТИ ДВИЖЕНИЯ ВОЗДУХА И ДАВЛЕНИИ В ИНЕРЦИОННОМ КОНЦЕНТРАТОРЕ

Various designs of inertial concentrators for cleaning dusty air are considered. The analyzed designs of devices for separating dust particles by fractions also have a number of disadvantages: low fractional efficiency and complexity of structures when divided into several fractions. The design of an inertial dust concentrator with adjustable parameters is proposed. This design of the concentrator provides an increase in fractional efficiency and a decrease in hydraulic resistance with the simplicity of the apparatus design. Three-dimensional modeling of the spatial motion of air in an inertial dust concentrator with adjustable parameters is performed. A system of equations describing gas-dynamic flows is given. The results of calculations of velocity and pressure in an inertial dust concentrator with adjustable parameters are presented. Reflecting vanes and a false wall inside an inertial concentrator act as deflectors, that is, deflect the flow, which leads to an increase in the time spent by suspended particles in the inertial concentrator and a decrease in their kinetic energy. In this case, the role of inertia forces on the motion of particles will increase. Numerical modeling of the three-dimensional air flow in the concentrator made it possible to obtain a flow pattern and the main flow characteristics (velocity and pressure) from the moment of air supply to the concentrator to the moment of establishing the flow.

Development of a technology for the production of aluminum-nickel calcium catalyst for steam conversion of natural gas

A technology has been developed for preparing a catalyst for primary reforming of natural gas of complex geometric shape, cylindrical with one hole and external grooves, by impregnating the support with a solution of nickel nitrate and aluminum nitrate at a ratio of NCl(NO3)2: Al (NO3)3 = 3: 1. The carrier was obtained from mixtures consisting of alumina, calcium hydroxide with the addition of wood flour or graphite. The residual methane content at 7000°, the space velocity of 6000 g-1, the ratio of gas = (2.0 ÷ 2.2): 1 does not exceed 5–7%, and the mechanical crushing strength along the tertz is at least 18 MPa. The decrease in hydraulic resistance in the catalyst bed and the simultaneous increase in the geometric and specific surface of the catalyst granules can dramatically increase the performance of the units or while maintaining the gas load, reduce the cost of compression, significantly increase the service life of the reaction tubes. The GIAP-16 catalyst is more refractory than the GIAP-5 and 2 grades are produced: Grade A based on aluminum oxide and Grade B based on aluminum hydroxide. Production technology is reduced to the following operations.

РЕЗУЛЬТАТЫ МОДЕЛИРОВАНИЯ ПРОЦЕССА ТЕЧЕНИЯ ЖИДКОСТИ В СКВАЖИННОМ САМООЧИЩАЮЩЕМСЯ ФИЛЬТРЕ

Актуальность исследования обусловлена необходимостью создания оптимальных фильтров, конструкция и физические принципы которых обеспечивают замедление процессов кольматации, снижение гидравлического сопротивления и длительный период эксплуатации. Цель: разработать самоочищающийся фильтр оптимальной, с точки зрения гидродинамики, конструкции. Объект: скважинный самоочищающийся фильтр, требующий улучшения гидродинамических характеристик течения жидкости за счет изменения конструкции перфорационных отверстий. Методы: компьютерное моделирование гидродинамической задачи течения жидкости в скважинном самоочищающемся фильтре с использованием прикладного программного продукта SolidWorks. Результаты. Описана предложенная авторами конструкция частицеудерживающего скважинного самоочищающегося фильтра, оснащенная системой вращающихся постоянных магнитов. Магнитное поле, создаваемое при вращении постоянных магнитов, обеспечивает существенное снижение процессов кольматации. Дальнейшее совершенствование конструкции связано с понижением гидравлического сопротивления, препятствующего проникновению откачиваемой жидкости в полость фильтра. Приведена методика создания имитационной модели для решения внутренней гидродинамической задачи течения жидкости в скважинном самоочищающемся фильтре с использованием прикладного программного пакета SolidWorks. Моделирование предназначено для имитации прохождения текучей среды (воды) через цилиндрические отверстия в стенке фильтра в направлении снаружи внутрь. Исследованы гидродинамические эффекты и основные физические параметры, имеющие место в результате прохождения жидкости через цилиндрические перфорационные отверстия. Выполненное моделирование течения откачиваемой жидкости в скважинном самоочищающемся фильтре позволило установить оптимальную конструкцию сверления перфорационных отверстий в каркасе фильтра и оптимальную длину фильтра, равную 0,4 мощности пласта.

HYDRAULIC RESISTANCE OF NON-NEWTONIAN TIME INDEPENDENT POWER LAW FLUIDS IN ROUGH PIPES USING DRAG REDUCING AGENTS

Background The pressure gradient prediction and the turbulent flows hydraulic resistance estimation are of great industrial importance. There are practically no researches in the literature to calculate the decrease in hydraulic resistance using drag reducing polymers for non-Newtonian time independent power law fluids in rough pipes. Aims and Objectives Calculation of hydraulic resistance for non-Newtonian time independent power law fluids in rough pipes using drag reducing polymers. Methods Mathematical modeling and numerical calculations for determining the hydraulic resistance coefficient based on the construction of velocity profiles in a rough tube of non-Newtonian time independent power law fluid with polymer additives. Results An implicit equation to determine the hydraulic resistance coefficient of time independent power law fluid using polymer additives agents in rough pipes is obtained. The polymer additives hydraulic efficiency of the flow of non-Newtonian time independent power law fluid in a rough pipe is higher comparing with a flow of a Newtonian fluid.

HYDRAULIC RESISTANCE OF TURBULENT FLOWS IN ROUGH PIPES USING DRAG REDUCING AGENTS

Background Prediction of the pressure gradient and estimation of the hydraulic resistance of turbulent flows are of great industrial importance. In the literature, there are practically no studies on calculating the reduction in hydraulic resistance using polymer additives for turbulent flows in rough pipes. Aims and Objectives Calculation of hydraulic resistance of turbulent flows in rough pipes using polymer additives. Methods Mathematical modeling and numerical calculations of determining the hydraulic resistance coefficient in rough pipes using drag reducing agents. Results A review of the works on the calculation of the decrease in hydraulic resistance by polymer additives in rough pipes is carried out. A comparative analysis of calculations based on various methods of hydraulic resistance coefficient and comparison with the available experimental data in the literature are presented.

Intensification of gas flow purification from finely dispersed particles by means of rectangular separator

The article considers the issues of gas flow purification from solid particles of small diameters 1-10 μm. The comparison of the efficiency of collecting the finely dispersed particles by rectangular separator and cyclonic separator CN-11 was conducted. The design of a rectangular separator and results of the finely dispersed particles settling on the I-beams of device were introduced. It was shown that different arrangement of I-shaped elements in the device and ratios between them have a significant impact on efficiency of collecting the finely dispersed particles of small diameters. The study of collecting the finely dispersed particles was conducted by means of the software package ANSYS Fluent. The numerical simulation was conducted by solving differential equations of motion and continuity. The turbulence model – SST was used in order to close the system of equations. Here we can find the results of computer simulation and impact analysis of dimensions of the I-shaped elements’ projections on the separator’s efficiency. The maximum efficiency of separator is achieved when the ratio of the I-beam projection towards its length is equal to 0.2428. The use of a rectangular separator provides an increase in the specific surface area of the contact of phases with a simultaneous decrease in hydraulic resistance against the gas flow.

Inherent Safety Characteristics of Advanced Fast Reactors

The study presents SFR transient performance for ULOF events initiated by pump trip and pump seizure with simultaneous failure of all shutdown systems in both cases. The most severe cases leading to the pin cladding rupture and possible sodium boiling are demonstrated. The impact of various features on SFR inherent safety performance for ULOF events was analysed. The decrease in hydraulic resistance of primary loop and increase in primary pump coast down time were investigated. Performing analysis resulted in a set of recommendations to varying parameters for the purpose of enhancing the inherent safety performance of SFR. In order to prevent the safety barrier rupture for ULOF events the set of thermal hydraulic criteria defining the ULOF transient processes dynamics and requirements to these criteria were recommended based on achieved results: primary sodium flow dip under the natural circulation asymptotic level and natural circulation rise time.

Effect of filler incorporation route on the properties of polysulfone–silver nanocomposite membranes of different porosities

Flat sheet porous polysulfone–silver nanocomposite membranes were synthesized by the wet phase inversion process. The effects of casting mixture composition and nanoparticle incorporation route on the morphological and separation properties of prepared membranes were studied by comparing nanocomposites of different preparations with silver-free controls. Silver nanoparticles were either synthesized ex situ and then added to the casting solution as an organosol or produced in the casting solution via in situ reduction of ionic silver by the polymer solvent. Nanocomposite membranes of three types differing in skin porosity and macrovoid structure were prepared. The structure and properties of nanocomposites were interpreted in terms of the coupling between the processes of nanoparticle formation and gelling of the polymer-rich phase during phase inversion. Larger nanoparticles preferentially located in the skin layer were observed in composites prepared via the ex situ method while in situ reduction of silver led to formation of smaller nanoparticles homogeneously distributed along the membrane cross-section. In some cases, incorporation of nanoscale silver formed ex situ resulted in macrovoid widening and an order of magnitude decrease in hydraulic resistance accompanied by only a moderate decrease in rejection. The accessibility of the silver nanoparticles embedded in the membrane was quantitatively assessed by the degree of the growth inhibition of a membrane biofilm due to the ionic silver released by the nanocomposites and was found to depend on the method of silver incorporation.

Dynamic changes in root hydraulic properties in response to nitrate availability

Changes in root hydraulic resistance in response to alterations in nitrate supply were explored in detail as a potential mechanism that allows plants to respond rapidly to changes in their environment. Sunflower (Helianthus annuus cv. Holiday) plants grown hydroponically with limited nitrate availability (200 micromol l(-1)) served as our model system. Experimental plants were 6-9-weeks-old with total dry mass of 2-4 g. Root pressurization of intact plants and detached root systems was used to elucidate the temporal dynamics of root hydraulic properties in sunflower plants following changes in external nitrate availability. The response was rapid, with a 20% decrease in hydraulic resistance occurring within the first hour after the addition of 5 mM nitrate and the magnitude of the effect was dependent on nitrate concentration. The change in root hydraulic resistance was largely reversible, although the temporal dynamics of the response to nitrate addition versus nitrate withdrawal was not symmetric (a gradual decrease in resistance versus its fast increase), raising the possibility that the underlying mechanisms may also differ. Evidence is presented that the observed changes in root hydraulic properties require the assimilation of nitrate by root cells. The hydraulic resistance of roots, previously stimulated by the addition of nitrate, increased more than in control plants in low nitrate under anoxia and that suggests a key role of aquaporin activity in this response. It is proposed that a rapid decrease in root hydraulic resistance in the presence of increased nitrate availability is an important trait that could enhance a plant's ability to compete for nitrate in the soil.

Rate Dependence of Hydraulic Resistance in Human Lumbar Vertebral Bodies

Twenty-one intact human lumbar vertebral bodies (L3 and L4) were used to determine the changes in measured intraosseous pressure for 2 volumetric flow rates and to calculate hydraulic resistance in both cases. To evaluate changes in hydraulic resistance in intact vertebral bodies under different rates of flow. Hydraulic resistance has been implicated in the creation of high-speed vertebral injuries, such as burst fracture, but no previous study has measured hydraulic resistance under high-speed loading conditions. Previous work in whole bone preparations showed that hydraulic resistance was constant under low-speed conditions. The authors hypothesized that: (1) measured pressure would increase with increasing input flow rates, and (2) hydraulic resistance would remain constant at increased input flow rates. Using 2 input velocity conditions (10 mm/s and 2500 mm/s), resultant pressures were measured and hydraulic resistance calculated. Trabecular architecture was determined using micro-computerized tomography after testing. Measured pressure increased with increasing input flow rates. However, average hydraulic resistance decreased significantly when comparing low-speed (3.40 +/- 1.58kPa*s/mL) and high-speed (0.16 +/- 0.08kPa*s/mL) groups. Current hydraulic resistance results contradict previous findings. The observed decrease in hydraulic resistance suggests that, during high-speed injury events, marrow flow may damage the trabeculae and thereby weaken the vertebra.

Strict metabolic control and renal function in the streptozotocin diabetic rat

Micropuncture studies were made on insulin-treated streptozotocin diabetic rats two weeks after the induction of diabetes and on age-matched control rats. Kidney size, GFR and single nephron GFR were higher in poorly controlled diabetic rats than in normal animals. Single nephron GFR rose as a result of an increase in the hydraulic pressure difference across the glomerular capillary wall caused mainly by a rise in the glomerular capillary pressure due to a diminished ratio of afferent to efferent arteriolar hydraulic resistances. Furthermore, the intratubular pressure was reduced as a result of a decrease in hydraulic resistance in the loop of Henle. Strict metabolic control prevented these changes. In conclusion, the increase in renal function in experimental diabetes is determined by the degree of metabolic control excluding a potential nephrotoxic effect of streptozotocin per se.