Showing papers on "Countercurrent exchange published in 2009"
TL;DR: In this paper, the viscous coupling effects for immiscible two-phase (gas-liquid) flow in porous media were studied using the Shan-Chen type single-component multiphase lattice Boltzmann model.
Abstract: In this paper, the viscous coupling effects for immiscible two-phase (gas-liquid) flow in porous media were studied using the Shan–Chen-type single-component multiphase lattice Boltzmann model. Using the model, the two-phase flows in porous media with density ratio as high as 56 could be simulated and the contact angle of the gas-liquid interface at a solid wall is adjustable. To investigate viscous coupling effects, the co- and countercurrent steady-state two-phase flow patterns and relative permeabilities as a function of wetting saturation were obtained for different capillary numbers, wettabilities, and viscosity ratios. The cocurrent relative permeabilities seem usually larger than the countercurrent ones. The opposing drag-force effect and different pore-level saturation distributions in co- and countercurrent flows may contribute to this difference. It is found that for both co- and countercurrent flows, for strongly wet cases and viscosity ratio M>1, knw increase with the driving force and the vis...
127 citations
TL;DR: In this paper, the authors describe the application of ceramic foam to distillation and develop a set of correlations describing pressure drop and liquid hold-up in terms of a dimensionless number.
82 citations
TL;DR: In this article, the effects of a countercurrent gas flow and liquid feeding length on falling-film mode transitions for a liquid flowing over horizontal tubes were explored. And a correlation was developed to predict the countercurrent flow effects on falling film mode transitions.
45 citations
TL;DR: A mathematical model is developed for this intermittent dual CCC system to predict retention time of the analytes, and using a simplified model system the validity of the model is justified by a series of basic studies on both hydrodynamic and hydrostatic CCC systems with a computer-programmed single sliding valve.
43 citations
TL;DR: In this paper, the evolution of excited waves on a viscous liquid film has been investigated experimentally for the annular gas-liquid flow in a vertical tube for the first time.
42 citations
TL;DR: In this article, a method for driving rotation and countercurrent flow in a fully ionized plasma centrifuge is described, where the rotation is produced by radiofrequency waves near the cyclotron resonance.
Abstract: A method for driving rotation and a countercurrent flow in a fully ionized plasma centrifuge is described. The rotation is produced by radiofrequency waves near the cyclotron resonance. The wave energy is transferred into potential energy in a manner similar to the α channeling effect. The countercurrent flow may also be driven by radiofrequency waves. By driving both the rotation and the flow pattern using waves instead of electrodes, physical and engineering issues may be avoided.
36 citations
TL;DR: In this article, the void fraction and film thickness of pure R-134a flowing downwards in a vertical condenser tube are indirectly determined using relevant measured data together with an annular flow model and various void fraction models reported in the open literature.
35 citations
TL;DR: In this article, a predictive model is developed to describe heat transfer and fluid dynamic behavior of a helical double-pipe vertical evaporator used in an absorption heat transformer integrated to a water purification process.
32 citations
Patent•
10 Dec 2009
TL;DR: In this paper, a countercurrent process for converting solid biomass material is described, where the solid biomass is subjected to a first conversion at a first temperature T 1 and a second conversion at the second temperature T 2 such that T 2 > T 1.
Abstract: A countercurrent process is disclosed for converting solid biomass material. The solid biomass material travels through a reactor system in countercurrent with hot heat carrier materials, such as particulate heat earner material and hot gases. The solid biomass material is subjected to a first conversion at a first temperature T 1. and a second conversion at a second temperature, T 2, such that T 2 > T 1. Bio-oil produced to at T J is not exposed to the higher temperature T 2. As a result, secondary reactions of the bio-oii components are minimized.
31 citations
TL;DR: In this paper, the effect of various parameters on the maximum heat flux of a vertical closed-loop pulsating heat pipe (CLPHP) and the inside phenomena that cause maximum heat flow to occur were investigated.
Abstract: The objective of this study is to experimentally investigate the effect of various parameters on the maximum heat flux of a vertical closed-loop pulsating heat pipe (CLPHP) and the inside phenomena that cause maximum heat flux to occur. A correlation to predict the maximum heat flux using the obtained results was also established. Quantitative and qualitative experiments were conducted and analyzed. A copper CLPHP and a transparent high-temperature glass capillary tube CLPHP were used in the quantitative and qualitative experiments. From the study, it was found that when the internal diameter and number of meandering turns increased, the maximum heat flux increased. However, when the evaporator section length increased, the maximum heat flux decreased. The maximum heat flux of a CLPHP occurs due to the dry-out of liquid film at the evaporator section. This occurs after a two-phase working fluid circulation changes flow pattern from countercurrent slug flow to co-current annular flow, because the vapor vel...
30 citations
TL;DR: In this article, a heat-integrated fuel cell stack system with methanol reforming is presented, which consists of fuel processing units (FPUs), proton exchange membrane (PEM) fuel cell stacks, and heat exchangers (HEXs).
TL;DR: In this article, a multiphase computational fluid dynamics (CFD) model was used to simulate the flow in the bubble column and to gain insights into the fluid dynamics of countercurrent flow bubble columns.
TL;DR: A continuous-flow countercurrent three-stage adsorption process was developed to provide for design in practical application and it was proved that large adsorbent savings were obtained from operations of these systems in most cases.
TL;DR: In this article, the cross-flow model is compared with the cocurrent flow model and the countercurrent flow model for the process of removing CO 2 from natural gas, and the results indicate that the membrane area is not a monodrome function of the selectivity and both the effects of the fast gas (CO 2 ) permeability and the slow gas (CH 4 ), on membrane area and CH 4 recovery are studied.
Abstract: In this work, the cross-flow model is compared with the cocurrent flow model and the countercurrent flow model for the process of removing CO 2 from natural gas. According to the comparison result, the cross-flow model is used for the analysis of the process of CO 2 removal from the natural gas. Analysis results indicate that the membrane area is not a monodrome function of the selectivity and both the effects of the fast gas (CO 2 ) permeability and the slow gas (CH 4 ) permeability on membrane area and CH 4 recovery are studied. Similar analysis is carried out for the operating pressures. Both the single stage system and the two-stage system with a recycle are studied. In order to reduce the membrane area required, membranes with high permeability and selectivity less than 100 are preferable. With increasing feed side pressure and decreasing permeate side pressure, the membrane area required decreases and the CH 4 recovery increases. For the single-stage system using a commercial membrane with selectivity of 20, the CH 4 recovery is lower than 90% at a product purity of 98%. Only when the membrane with selectivity higher than 50 is used, the separation of CH 4 recovery >98% and product purity >98% target can be fulfilled by the single stage system. Using the two-stage system with a membrane selectivity of 20, the separation target can be achieved. In the two-stage system, the permeate gas of the first stage has to be compressed before it can be sent to the next stage. The compression energy required between stages is estimated to be 107.5 KJ/m 3 (STP) of feed for the process discussed in this paper. Even considering the conversion factor between heat and electricity of 3-4, the energy consumption of a two-stage membrane system is still much less than that of the amine absorption process which is about 600-900 KJ/(m 3 (STP) of feed).
TL;DR: The behavior of continuous and discrete phases in countercurrent spray drying process is described in this paper, and the mechanism of moisture evaporation and hydrodynamics of the discrete phase are discussed.
Abstract: The behavior of continuous and discrete phases in countercurrent spray drying process is described in the article. Literature and our own experimental results on spray drying in the countercurrent system are presented and the mechanism of moisture evaporation and hydrodynamics of the discrete phase are discussed. Negative values of particle velocity were found in the drying chamber, which confirmed the existence of recirculation zones where agglomeration of particles took place. An increase of mean particle size with the distance from the nozzle caused by agglomeration in recirculation zones in the column was also observed. High sensitivity of the discrete-phase flow pattern to small changes in drying and atomization parameters and the nozzle position in the dryer was found. Analysis of the results proved that due to complicated hydrodynamics of the continuous and disperse phases, a narrow range of stable operating parameters, and significant changes in final product properties at slight changes of drying...
Patent•
14 Mar 2009
TL;DR: In this article, the chromatography column is replaced by a module that consists of two or more interconnected tangential flow filters and static mixers, and the buffers for these operations are pumped into the module in a countercurrent direction to the flow of resin, and permeate solutions from later stages are recycled back into previous stages.
Abstract: This invention relates to a breakthrough in the art of chromatography allowing 1) larger scale of operation; 2) faster processing time; 3) disposability; 4) reduction of media/resin expenses; and 5) a reduction of capital equipment investment. In this invention, the chromatography column is replaced by a module that consists of two or more interconnected tangential flow filters and static mixers. The chromatography resin flows through this module in a single pass, while similar operations to a regular chromatographic process are performed on the resin (binding, washing, elution, regeneration, and equilibration). The buffers for these operations are pumped into the module in a countercurrent direction to the flow of resin, and permeate solutions from later stages are recycled back into previous stages. This creates concentration gradients in the permeate solutions of the tangential flow filters in the countercurrent direction to resin flow, thus saving buffer volume and increasing process efficiency.
TL;DR: In this paper, a bubbling countercurrent multistage fluidized-bed reactor for the sorption of sulfur dioxide by hydrated lime particles was simulated employing a two-phase model, with the bubble phase assumed to...
Abstract: A bubbling countercurrent multistage fluidized-bed reactor for the sorption of sulfur dioxide by hydrated lime particles was simulated employing a two-phase model, with the bubble phase assumed to ...
TL;DR: In this paper, a mathematical model for the mass transfer in a parallel plate countercurrent dialysis system coupled with ultrafiltration operation was developed theoretically and experimentally in order to obtain the analytical solution using the Frobenius series method.
Patent•
20 Jul 2009
TL;DR: In this paper, the authors describe a capillary tube register comprising at least one mat formed from longitudinal (1) and lateral (2) capillary tubes connected together in a mesh pattern for fluid throughput.
Abstract: In a heat exchanger comprising a capillary tube register in which a fluid to be cooled and/or heated is routed through capillary tubes and in which air flows around the capillary tubes in countercurrent flow relative to the fluid, the capillary tube register comprises at least one capillary tube mat formed from longitudinal (1) and lateral (2) capillary tubes connected together in a mesh pattern for fluid throughput. At least the longitudinal capillary tubes are each connected by way of the ends thereof to a common trunk (3) for feeding, and to a common trunk (4) for discharging, the fluid.
TL;DR: In this paper, boundary conditions for asymmetric wall heat fluxes in double-pass parallel-plate laminar countercurrent operations are analyzed theoretically by using an eigenfunction expansion in terms of power series for the homogeneous part and an asymptotic solution for the non-homogeneous part.
01 Jan 2009
Patent•
12 Mar 2009
TL;DR: In this paper, the authors proposed a countercurrent total heat exchanger with less adhered portions and a larger effective heat transfer area resulting in high heat exchanging efficiency in principal, where a plurality of heat exchanging members 20 each consisting of a partition film and a flow path forming member 2 adhered to the partition film 1 to form a flowpath 7, and laminated up and down for exchanging sensible heat and latent heat between two types of gas via the partition films 1.
Abstract: PROBLEM TO BE SOLVED: To provide a countercurrent total heat exchanger having less adhered portions and a larger effective heat transfer area resulting in high heat exchanging efficiency in principal. SOLUTION: The countercurrent total heat exchanger comprises a plurality of heat exchanging members 20 each consisting of a partition film 1 and a flow path forming member 2 adhered to the partition film 1 to form a flow path 7, and laminated up and down for exchanging sensible heat and latent heat between two types of gas via the partition films 1. The flow path forming member 2 consists of a plurality of frame members 3 arranged along an outer edge 1a of the partition film 1, and thin rib materials 4 arranged between the two frame members 3 at predetermined spaces and each having a width smaller than the width of the frame member 3. In an inlet 5 and an outlet 6 of the flow path 7, a strip-shaped cardboard member 9A is provided for preventing shape changes of the inlet 5 and the outlet 6. COPYRIGHT: (C)2009,JPO&INPIT
Patent•
14 Jan 2009
TL;DR: In this article, a lightweight hydrocarbon hydrogenising method is proposed, which adopts a first stage countercurrent hydrogenising reactor and a conventional co-current hydrogenizing reactor connected in series.
Abstract: The invention discloses a lightweight hydrocarbon hydrogenising method, which adopts a first stage countercurrent hydrogenising reactor and a conventional co-current hydrogenising reactor connected in series. The raw material enters into a flash evaporation area of the countercurrent hydrogenising reactor at a lower temperature, gas-phase hydrocarbon flows upwards and performs a reaction of diene and mercaptan producing sulfide and a diene hydrogenising reaction at the upper part of the countercurrent hydrogenising reactor, high boiling sulfide generated by the upper part reaction and liquid-phase hydrocarbon after the raw material flash evaporation flow downwards together, and an alkylation reaction of thiophene sulfur and olefin is generated; Hydrogen enters at the bottom of the countercurrent hydrogenising reactor and flows upwards. Liquid phase discharged at the bottom of the countercurrent hydrogenising reactor and new hydrogen are mixed and enter into the co-current hydrogenising reactor to perform the reactions, such as deep hydrodesulfurization, selective cracking or isomerization and the like after being heated. The method has the advantages that the technological process is simple, the desulphurization effect is good, the octane value loss is low, the product yield is high, and the required equipment is few. The method is mainly used for the secondary processing the poor-quality gasoline, namely, the upgrading process of catalytic cracking gasoline, coking gasoline or thermal cracking gasoline.
TL;DR: In this article, the effects of external recycle at the ends on double-pass laminar countercurrent heat exchangers with sinusoidal heat flux distribution are investigated analytically by setting a general solution to separate the original boundary value problem into a partial differential equation, which is solved by Frobenius method, and an ordinary differential equation.
TL;DR: In this article, the internal and discharge flow of a positive discharge blower with involute type three-lobe were numerically investigated, both in air cooling and countercurrent cooling conditions by means of computational fluid dynamics (CFD).
Abstract: The operating performance of positive discharge blower is markedly influenced by the pulsation of the discharge flow, but difficult to be measured with experimental methods. The internal and discharge flow of positive discharge blower with involute type three-lobe are numerically investigated, both in air cooling and countercurrent cooling conditions by means of computational fluid dynamics (CFD). The unsteady compressible flow equations are solved using RNG κ-e turbulent model. The finite difference method and the second order upwind difference scheme are applied into discrete equations. In the numerical simulation, the dynamic mesh techniques are used to approach the rotating displacement of cell cubage and the alterability of inlet, outlet flow area. The non-uniform mesh is applied to the rotor-stator coupled area. The reliability of the numerical method is verified by simulating the inner flow and comparing with the semi-empirical theory. The flow flux curves and the distributing of velocity vector showed obvious vortex motion in all the discharge process, both in air cooling and countercurrent cooling conditions. These vortexes with different positions, intension and numbers at different rotating angles have remarkable influences on the discharge flux. For air cooling, the vortex produced a second pulsation with big-amplitude in a cycle, and led to the early appearance of maximum of backflow. For countercurrent cooling, the frequency of pulsation increased due to the pre-inflow, but the backflow at the outlet is prevented, also the pulsation strength has greatly decreased.
TL;DR: In this paper, the conjugated Graetz problem is solved analytically by using an eigenfunction expansion in terms of power series for the homogeneous part and an asymptotic solution for the inhomogeneous part.
Abstract: A device involving mass exchangers with a permeable membrane inserted to divide the open duct into two subchannels for conducting double-pass laminar countercurrent operations under asymmetric wall mass fluxes, which results in a substantial improvement of the mass transfer, has been developed and investigated theoretically. The resultant partial differential equations for such a double-pass forced-convection mass transfer problem are referred to as conjugated Graetz problems and solved analytically in this work by using an eigenfunction expansion in terms of power series for the homogeneous part and an asymptotic solution for the inhomogeneous part. The theoretical predictions of mass transfer efficiency improvement in double-pass, parallel-plate mass exchangers are obtained by suitably adjusting the permeable membrane location. They are represented graphically and compared with the results from an open duct of a single-pass operation (without a permeable membrane inserted). The increment of power consumption is also discussed.
Patent•
19 Nov 2009
TL;DR: In this paper, the authors proposed a countercurrent plate fin type heat exchanger capable of reducing heat conduction via a structure material from a high temperature side to a low temperature side, and an air cycle refrigeration system for a container capable of improving refrigeration capacity by improvement of the heat exchange efficiency.
Abstract: PROBLEM TO BE SOLVED: To provide a countercurrent plate fin type heat exchanger capable of reducing heat conduction via a structure material from a high temperature side to a low temperature side and improving heat exchange efficiency, and an air cycle refrigeration system for a container capable of improving refrigeration capacity by improvement of the heat exchange efficiency. SOLUTION: In this heat exchanger for heat release or heat exchanger for heat recovery as the countercurrent plate fin type heat exchanger, heat insulating materials 21 for blocking heat conduction in a flow passage flowing direction via plates 20 and heat conduction fins 19 are provided in a plurality of sections in the flow passage flowing direction of a heat exchanger body. COPYRIGHT: (C)2010,JPO&INPIT
Patent•
16 Jul 2009
TL;DR: The countercurrent direct-heating-type heat exchanger that is able to suppress drift in the case when a fluid to be heated is supplied, to prevent local abrasion of the members and also to carry out efficient heat exchange is described in this article.
Abstract: The countercurrent direct-heating-type heat exchanger that is able to suppress drift in the case when a fluid to be heated is supplied, to prevent local abrasion of the members and also to carry out efficient heat exchange. The countercurrent direct-heating-type heat exchanger equipped with a feed pipe, a feed nozzle, ring-like straightening plates and umbrella-type dispersing plates of the above fluid to be heated, characterized in that the above feed nozzle has the shape of a pipe having a circular cross section and the dimension satisfying the following formula (1) and formula (2): Ln/Dn ≧1 Formula (1) (wherein, Ln indicates the length of the feed nozzle; and Dn indicates the inside diameter of the feed nozzle) 1.5≦ Sp/Sn ≦2.0 Formula (2) (wherein, Sp indicates the inner cross-sectional area of the feed pipe; and Sn indicates the inner cross-sectional area of the feed nozzle).
TL;DR: In this article, the authors investigated the heat transfer process in a cyclone cyclone heat exchanger with tangentially swirled flow of gas suspension, separation of solid particles on the heat-exchanger walls, and deceleration of flue gas flows as they collide with the charge mixture fed to the apparatus.
Abstract: Heat-transfer processes in a countercurrent cyclone heat exchanger are investigated on a pilot installation. Volumetric coefficients of heat transfer from gases to a flow of solid particles are determined during operation with tangentially swirled flow of gas suspension, separation of solid particles on the heat-exchanger walls, and deceleration of flue gas flows as they collide with the charge mixture fed to the apparatus.
01 Jan 2009
TL;DR: Results indicate that the countercurrent multiplier system is useful to develop an artificial renal tubule, and the fabricated prototype module was capable of concentrating urea approximately 1.3 fold.
Abstract: Countercurrent multiplier systems have been found in various organs of various animal species. In a mammalian kidney, countercurrent multiplier system plays an important role in the process of urine concentration. An artificial renal tubule which can concentrate urea is one of the key elements to develop a wearable artificial kidney for the patients currently undergoing intermittent hemodialysis therapy. The objective of the present study was to develop a biomimetic artificial renal tubule based on the countercurrent multiplier system. We mimicked active transport of NaCl at ascending limbs of the Henle loop by electrodialysis and mimicked passive transport of the solute and water transport via water channel at descending limbs and collecting ducts by dialysis and filtration. The membranes used for electrodialysis, dialysis and filtration were placed parallel to each other to establish countercurrent configuration. We examined urea concentrating ability of the fabricated prototype module of artificial renal tubule based on the countercurrent multiplier system. The fabricated prototype module was capable of concentrating urea approximately 1.3 fold. These results indicate that the countercurrent multiplier system is useful to develop an artificial renal tubule.