THE MICROPORE FLOW OF H2O AND D2O THROUGH ACTIVATED CARBON RODS

1956 ◽  
Vol 34 (9) ◽  
pp. 1288-1301 ◽  
Author(s):  
M. E. Huber ◽  
E. A. Flood ◽  
R. D. Heyding
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
Relative Viscosity ◽  
Adsorbed Water ◽  
Liquid Films ◽  
Surface Forces ◽  
Sudden Increase ◽  
Flow Data ◽  
Flow Rates ◽  
Carbon Rods

The flow rates of water adsorbed on activated charcoal have been measured at temperatures between −24 °C. and +35 °C. and compared with the flow rate of adsorbed D2O at 25 °C. In earlier papers a formula was presented which describes the micropore flow rate of adsorbed water as a laminar flow of liquid adsorbate under a high pressure gradient due to surface forces. Our results confirm this picture. From our flow data the relative viscosity of adsorbates can be calculated. Above 0 °C. the viscosity of the adsorbate shows nearly the same temperature dependence as liquid water; below 0 °C. the viscosity increases much more rapidly, but there is no sudden increase which could be ascribed to freezing of an appreciable fraction of the adsorbate at any particular temperature. The greater temperature coefficient of the adsorbate viscosity is consistent with a viscous flow of liquid films over a solid surface which exerts attractive forces on the liquid.

Analysis of Static Characteristics of Pressure Seal in Actual High Pressure Pump

2011 ◽  
Author(s):  
Isao Hagiya ◽  
Katsutoshi Kobayashi ◽  
Yoshimasa Chiba ◽  
Tetsuya Yoshida ◽  
Akira Arai
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
High Speed ◽  
Control Volume ◽  
Leakage Flow ◽  
High Pressure Pump ◽  
Flow Rates ◽  
Leakage Flow Rate ◽  
Rotor Dynamic ◽  
Pressure Seal

We predicted the leakage flow rates of a pressure seal in an actual high-pressure multistage pump. Since the pressure of the actual pump is higher than that of a model pump, accurate prediction of leakage flow rate and rotor dynamic forces for an actual pump is more difficult than that for a model pump. A non-contacting seal is used as a pressure seal to suppress leakage flow for high-pressure multistage pumps. When such pumps are operated at high speed, the fluid force acting on an eccentric rotor may cause vibration instability. For vibration stability analysis, we need to estimate static and dynamic characteristics of the pressure seals, i.e., leakage flow rate and rotor dynamic coefficients. We calculated the characteristics of the pressure seal based on Iwatsubo group’s method. The pressure seal we developed has labyrinth geometry consisting of grooves with different sizes. This method numerically calculates the characteristics of the grooved seal by using a three-control-volume model and a perturbation method. We compared the calculated and measured leakage flow rates. We found that the calculated results quantitatively agreed with the measured one in the actual pump and the characteristics of pressure and velocity for the seal with non-uniform-sized grooves were clarified.

Development of Robust Microvavles for Compact Robust Pumps/Hydraulic Actuators

2007 ◽  
Vol 121-123 ◽  
pp. 1207-1210
Author(s):  
B. Li ◽  
Q. Chen
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
Pressure Support ◽  
Test Results ◽  
Valve Design ◽  
Standard Process ◽  
Flow Rates ◽  
Forward Flow ◽  
Large Flow

In situ UV-LIGA assembled robust micro check valves with large flow rates (>10 ml/s, displacement related), high-pressure support ability (>10 MPa) and high operational frequencies (>10 kHz) made of nano-structured nickel were presented in this paper. The microvalve consists of an array of 80 single micro valves to achieve the required flow rates. Test results show that the forward flow rate is about 19 ml/s under pressure of 90Psi. The backward flow rate is negligible. The reliability of the valve is ensured by the valve design and nanostructured nickel realized. The tested tensile strength of a nano structured nickel is about 1GPa. The strength of SU-8 is 50MPa, which is more than 50% higher that fabricated with a standard process.

scholarly journals Theoretical and Experimental Studies of a Digital Flow Booster Operating at High Pressures and Flow Rates

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 211 ◽  
Author(s):  
Chenggang Yuan ◽  
Vinrea Lim Mao Lung ◽  
Andrew Plummer ◽  
Min Pan
Keyword(s):  
Energy Efficiency ◽  
High Pressure ◽  
Flow Rate ◽  
High Energy ◽  
Control Flow ◽  
Fluid Power ◽  
Analytical Models ◽  
Operating Pressure ◽  
Hydraulic Systems ◽  
Flow Rates

The switched inertance hydraulic converter (SIHC) is a new technology providing an alternative to conventional proportional or servo-valve-controlled systems in the area of fluid power. SIHCs can adjust or control flow and pressure by means of using digital control signals that do not rely on throttling the flow and dissipation of power, and provide hydraulic systems with high-energy efficiency, flexible control, and insensitivity to contamination. In this article, the analytical models of an SIHC in a three-port flow-booster configuration were used and validated at high operating pressure, with the low- and high-pressure supplies of 30 and 90 bar and a high delivery flow rate of 21 L/min. The system dynamics, flow responses, and power consumption were investigated and theoretically and experimentally validated. Results were compared to previous results achieved using low operating pressures, where low- and high-pressure supplies were 20 and 30 bar, and the delivery flow rate was 7 L/min. We concluded that the analytical models could effectively predict SIHC performance, and higher operating pressures and flow rates could result in system uncertainties that need to be understood well. As high operating pressure or flow rate is a common requirement in hydraulic systems, this constitutes an important contribution to the development of newly switched inertance hydraulic converters and the improvement of fluid-power energy efficiency.

THE FLOW OF FLUIDS THROUGH ACTIVATED CARBON RODS: II. THE PORE STRUCTURE OF ACTIVATED CARBON

1952 ◽  
Vol 30 (4) ◽  
pp. 372-385 ◽  
Author(s):  
E. A. Flood ◽  
R. H. Tomlinson ◽  
A. E. Leger
Keyword(s):  
Activated Carbon ◽  
Zinc Chloride ◽  
Activated Carbons ◽  
Surface Forces ◽  
Flow Measurements ◽  
Flow Rates ◽  
Frequency Distributions ◽  
Carbon Rods ◽  
Ordinary Type ◽  
Flow Through

The flow rates of adsorbable gases through zinc chloride activated carbon rods are considerably greater than might be expected from classical considerations. From data independent of flow measurements, the pore-size frequency distributions of the activated carbon are deduced and a model macropore system presented. It is shown that flow rates of nonadsorbable gases are consistent with a mean macropore diameter of about 3 × 10−5 cm., as well as being consistent with what can be inferred concerning such structures. The macropore system is regarded as an interstitial structure and is described as a random assembly of "bottle necks" joining relatively large void spaces. The assembly is described by means of two constant parameters and one stochastic variable. The mean micro-pore diameter of zinc chloride activated carbons is generally regarded as being of the order of 2 × 10−7 cm. or less. It is shown that no ordinary type of effusive or diffusive flow through pores of the order of 2 × 10−7 cm. can be appreciable compared with the flow through the macropore system, unless surface forces increase flow rates by large factors. In the case of strongly adsorbed gases the anomalous flow rates are ascribed to a flow through the micropore system and hence it is inferred that surface forces introduce large factors tending to increase flow rates in these very small pores.

Design and Numerical Flow Analysis of a LNG Power Recovery Turbine

2013 ◽  
Author(s):  
Kaiqiang Li ◽  
Jinju Sun ◽  
Juntao Fu ◽  
Peng Song
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
Flow Behavior ◽  
Leading Edge ◽  
Cavitating Flow ◽  
Design Flow ◽  
Technical Requirement ◽  
Edge Region ◽  
Flow Rates ◽  
Overall Efficiency

The liquefaction process of natural gas often operates at high pressure level, thus the LNG product is of very high pressure and must be reduced to satisfy the technical requirement for storage and transportation. Traditionally, the high-pressure LNG is expanded isenthalpically by means of J-T valves but this introduces an unexpected temperature rise, leading to vaporization of LNG product and subsequently a reduced delivery. An efficient alternative is using the LNG expanders to replace the J-T valves and achieve a near-isentropic expansion and subsequently suppress the cavitation. In the present study, a single stage LNG turbine expander is developed as a replacement of J-T valve for the purpose of cavitation suppression. The cavitating flow behavior is investigated by using a multiphase cavitation model. The effect of impeller geometric parameters on the turbine flow and performance has been identified through sensitivity studies. The following are demonstrated: (1) The predicted turbine overall efficiency is 91.34%, shaft power delivery is 81.16kW, temperature drop is 0.84 K; and the overall vaporization rate is less than a percentage. (2) Cavitation is encountered in the impeller leading edge region and half stream-wise region, resulting respectively from the viscous dissipation and flow separation. (3) At larger than design flow rates, the predicted turbine overall efficiency decreases nonlinearly with the flow rate due to cavitation zone growth in the leading edge region; at lower than design flow rates, the overall efficiency increases with the flow rate, due to cavitation zone decrease in the half streamwise region. (4) Cavitating flow behavior is sensitive to impeller geometry tuning. Variation of the impeller inducer twist angle reduces the trialing edge cavitation and subsequently improves the turbine overall performance. (5) Cavitation flow behavior is also sensitive to the radial gap size of the nozzle and impeller.

THE FLOW OF FLUIDS THROUGH ACTIVATED CARBON RODS: III. THE FLOW OF ADSORBED FLUIDS

1952 ◽  
Vol 30 (5) ◽  
pp. 389-410 ◽  
Author(s):  
E. A. Flood ◽  
R. H. Tomlinson ◽  
A. E. Leger
Keyword(s):  
Empirical Equation ◽  
Flow Equation ◽  
Surface Forces ◽  
Physical Factors ◽  
Pressure Gradients ◽  
Total Flow ◽  
Flow Rates ◽  
Carbon Rods ◽  
Porous Adsorbent ◽  
Simple Flow

Total flow rates of gases through activated charcoal rods are regarded as consisting of the sums of comparatively independent flows through macropores and micropores. The flow rate through the macropore system is related to the relevant adsorption isotherm by means of an empirical equation having three arbitrary constants. The empirical equations can be fitted to all of our observed results within the experimental error. Assuming that the adsorbate behaves as a one-component fluid such as a gas in a gravitational field, it is shown that compressive surface forces give rise to large fluid pressures within micropores. A very simple flow equation is derived which is qualitatively in agreement with observed results and which indicates a mean micropore diameter, of the order of 10−7 cm. The derived equation illustrates the nature of the physical factors involved and shows that surface forces may increase flow rates of adsorbable gases by very large factors. The increased flow rates are due mainly to the greatly increased densities and to the increased pressure gradients resulting from the action of surface forces. A model porous adsorbent is presented which exhibits many properties of real adsorbent systems and illustrates especially the relations between adsorbate densities and the various tensions and pressures existing within micropore systems.

THERMODYNAMIC CONSIDERATIONS OF SURFACE REGIONS: ADSORBATE PRESSURES, ADSORBATE MOBILITY, AND SURFACE TENSION

1955 ◽  
Vol 33 (2) ◽  
pp. 203-214 ◽  
Author(s):  
E. A. Flood ◽  
Max Huber
Keyword(s):  
Surface Tension ◽  
High Pressure ◽  
Activated Carbon ◽  
Temperature Coefficient ◽  
Flow Rate ◽  
Liquid Water ◽  
Water Surface ◽  
High Pressures ◽  
Surface Forces ◽  
Pressure Gradients

The flow of water through the micropore system of activated carbon has been described in previous papers as a hydrodynamic flow of liquid water under high pressure gradients due to surface forces. It is shown below that these high pressures are probably real and that the temperature coefficient of the flow rate is closely related to the temperature coefficient of the viscosity of liquid water. Surface tension is discussed.

DETERMINATION OF THE LIMITING FLOW RATE IN LIQUID FILMS FOR HEAT TRAHSFER CRISIS CALCULATION

1978 ◽  
Author(s):  
V. M. Borishansky ◽  
A.A. Andreevsky ◽  
Mikhail Ya. Belenkiy ◽  
G.S Bykov ◽  
Mikhail Gotovskii ◽  
...  
Keyword(s):  
Flow Rate ◽  
Liquid Films

Hydraulic model of a water cooling system in a chemical plant

1988 ◽  
Vol 53 (4) ◽  
pp. 788-806
Author(s):  
Miloslav Hošťálek ◽  
Jiří Výborný ◽  
František Madron
Keyword(s):  
Flow Rate ◽  
Cooling System ◽  
Cooling Water ◽  
Graph Algorithm ◽  
Automatic Generation ◽  
Hydraulic Calculation ◽  
Return Flow ◽  
Flow Rates ◽  
Pressure Losses ◽  
Controlled Flow

Steady state hydraulic calculation has been described of an extensive pipeline network based on a new graph algorithm for setting up and decomposition of balance equations of the model. The parameters of the model are characteristics of individual sections of the network (pumps, pipes, and heat exchangers with armatures). In case of sections with controlled flow rate (variable characteristic), or sections with measured flow rate, the flow rates are direct inputs. The interactions of the network with the surroundings are accounted for by appropriate sources and sinks of individual nodes. The result of the calculation is the knowledge of all flow rates and pressure losses in the network. Automatic generation of the model equations utilizes an efficient (vector) fixing of the network topology and predominantly logical, not numerical operations based on the graph theory. The calculation proper utilizes a modification of the model by the method of linearization of characteristics, while the properties of the modified set of equations permit further decrease of the requirements on the computer. The described approach is suitable for the solution of practical problems even on lower category personal computers. The calculations are illustrated on an example of a simple network with uncontrolled and controlled flow rates of cooling water while one of the sections of the network is also a gravitational return flow of the cooling water.

scholarly journals Geometrical Optimization of a Venturi-Type Microbubble Generator Using CFD Simulation and Experimental Measurements

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 4
Author(s):  
Dillon Alexander Wilson ◽  
Kul Pun ◽  
Poo Balan Ganesan ◽  
Faik Hamad
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Air Flow ◽  
Bubble Diameter ◽  
Diameter Ratio ◽  
Experimental Measurements ◽  
Cfd Model ◽  
Flow Rates ◽  
Throat Diameter

Microbubble generators are of considerable importance to a range of scientific fields from use in aquaculture and engineering to medical applications. This is due to the fact the amount of sea life in the water is proportional to the amount of oxygen in it. In this paper, experimental measurements and computational Fluid Dynamics (CFD) simulation are performed for three water flow rates and three with three different air flow rates. The experimental data presented in the paper are used to validate the CFD model. Then, the CFD model is used to study the effect of diverging angle and throat length/throat diameter ratio on the size of the microbubble produced by the Venturi-type microbubble generator. The experimental results showed that increasing water flow rate and reducing the air flow rate produces smaller microbubbles. The prediction from the CFD results indicated that throat length/throat diameter ratio and diffuser divergent angle have a small effect on bubble diameter distribution and average bubble diameter for the range of the throat water velocities used in this study.

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