Capillary trees for passive pumping water

2021 ◽  
Author(s):  
Xuewei Zhang ◽  
Sylvie Lorente
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Capillary Flow ◽  
Search Algorithm ◽  
Geometrical Parameters ◽  
Maximum Mass ◽  
Capillary Flows ◽  
The Impact ◽  
Fixed Network

Abstract Capillary flows are an attractive feature for passive water harvesting as they require no external driving force to pull the fluid out within the capillary network. Here we analyze the architecture of capillary flow networks in steady state, and the impact of the network morphology on the maximum mass flow rate that can be extracted for a fixed network volume and fixed network footprint. We develop a search algorithm to test the possible location of all the junction and bifurcation nodes and the changes in diameter ratios with the objective of obtaining the maximum mass flow rate from the network. We define the Capillary Strength CS as a local indicator to determine the geometrical parameters of each conduct that allow to sustain the overall mass flow rate. It is shown that the diameter ratio of connected tubes for maximum mass flow rate depends on the distance from the network outlet, and therefore does not follow the Hess-Murray’s law. The superiority of dendritic architectures in the roots and canopy branches of the capillary trees is demonstrated.

Effect of Blade Angle of Attack and Hub to Tip Ratio on Mass Flow Rate in an Axial Fan at a Fixed Rotational Speed

2008 ◽  
Author(s):  
Mohammad J. Izadi ◽  
Alireza Falahat
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Angle Of Attack ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Maximum Mass ◽  
Blade Angle ◽  
Axial Fan

In this investigation an attempt is made to find the best hub to tip ratio, the maximum number of blades, and the best angle of attack of an axial fan with flat blades at a fixed rotational speed for a maximum mass flow rate in a steady and turbulent conditions. In this study the blade angles are varied from 30 to 70 degrees, the hub to tip ratio is varied from 0.2 to 0.4 and the number of blades are varied from 2 to 6 at a fixed hub rotational speed. The results show that, the maximum flow rate is achieved at a blade angle of attack of about 45 degrees for when the number of blades is set equal to 4 at most rotational velocities. The numerical results show that as the hub to tip ratio is decreased, the mass flow rate is increased. For a hub to tip ratio of 0.2, and an angle of attack around 45 degrees with 4 blades, a maximum mass flow rate is achieved.

Conjugate Heat Transfer Analysis on Generic Rim Seal Configurations in Rotor-Stator System

2018 ◽  
Author(s):  
Xingyun Jia ◽  
Liguo Wang ◽  
Qun Zheng ◽  
Hai Zhang ◽  
Yuting Jiang
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Analysis ◽  
Minimum Mass ◽  
Aerodynamic Efficiency ◽  
Axial Clearance ◽  
The Impact

Performance of generic rim seal configurations, axial-clearance rim seal (ACS), radial-clearance rim seal (RCS), radial-axial clearance rim seal (RACS) are compared under realistic working conditions. Conjugate heat transfer analysis on rim seal is performed in this paper to understand the impact of ingestion on disc temperature. Results show that seal effectiveness and cooling effectiveness of RACS are the best when compared with ACS and RCS, the minimum mass flow rate for seal of RACS is 75% of that of RCS, and 34.6% of ACS. Authors compare the disc temperature distribution between different generic rim seal configurations where the RACS seems to be favorable in terms of low disc temperature. In addition, RACS has higher air-cooled aerodynamic efficiency, minimizing the mainstream performance penalty when compared with ACS and RCS. Corresponding to the respective minimum mass flow rate for seal, the air-cooled aerodynamic efficiency of RACS is 23.71% higher than that of ACS, and 12.79% higher than the RCS.

scholarly journals On-Sun Performance Evaluation of Alternative High-Temperature Falling Particle Receiver Designs

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Clifford K. Ho ◽  
Joshua M. Christian ◽  
Julius E. Yellowhair ◽  
Kenneth Armijo ◽  
William J. Kolb ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Particle Temperature ◽  
Free Fall ◽  
Mass Flow Rates ◽  
Mesh Structures ◽  
Free Falling ◽  
The Impact

This paper evaluates the on-sun performance of a 1 MW falling particle receiver. Two particle receiver designs were investigated: obstructed flow particle receiver versus free-falling particle receiver. The intent of the tests was to investigate the impact of particle mass flow rate, irradiance, and particle temperature on the particle temperature rise and thermal efficiency of the receiver for each design. Results indicate that the obstructed flow design increased the residence time of the particles in the concentrated flux, thereby increasing the particle temperature and thermal efficiency for a given mass flow rate. The obstructions, a staggered array of chevron-shaped mesh structures, also provided more stability to the falling particles, which were prone to instabilities caused by convective currents in the free-fall design. Challenges encountered during the tests included nonuniform mass flow rates, wind impacts, and oxidation/deterioration of the mesh structures. Alternative materials, designs, and methods are presented to overcome these challenges.

Uncertainty Evaluation of the Natural Gas Molar Mass and Its Flow Rate Impact

2008 ◽  
Author(s):  
Elcio Cruz de Oliveira
Keyword(s):  
Natural Gas ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Molar Mass ◽  
Internal Diameter ◽  
Gas Measurement ◽  
Oil And Natural Gas ◽  
Mass Uncertainty ◽  
The Impact

In Brazil, the National Oil Agency — ANP and the National Metrology Institute elaborated Regulation No 1, on June 19th 2000. This government decree approves the Regulation of the Measurement Technique of Oil and Natural Gas, which establishes the minimum conditions and requirements for the oil and natural gas measurement systems, in order to guarantee accurate and complete results. The natural gas measurement fiscal systems must be projected, calibrated and operated so that the measurement uncertainty does not exceed 1.5%. Based on the norms AGA and ISO, the mathematical model for the calculation of the mass flow rate, depends on quantities that have well known uncertainty such as: orifice plate diameter, pipeline internal diameter, compressibility factor, discharge coefficient, differential pressure, static pressure and flow temperature. However, for the molar mass standard uncertainty fixed values are utilized in Brazil (mainly by IPT and PUC-RJ), around 0.30%, independent of the natural gas composition. The objective of this work is to develop a methodology to calculate the molar mass uncertainty of the natural gas derived from its chemical composition, analyzed by gaseous chromatography and to comparing it with the value currently practiced, evaluating the impact proceeding from this difference in the mass flow rate of the natural gas. Based on this methodology, the molar mass uncertainty is around 0.05% and the fiscal system uncertainty decreases in more than 10% when it is compared with the mass molar fixed value uncertainty.

Unsteady Interaction Between Annulus and Turbine Rim Seal Flows

2012 ◽  
Author(s):  
Martin Chilla ◽  
Howard Hodson ◽  
David Newman
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Turbines ◽  
Measurement Data ◽  
Design Flow ◽  
Flow Conditions ◽  
Disc Space ◽  
Flow Interaction ◽  
The Impact

In core gas turbines relatively cold air is purged through the hub gap between stator and rotor in order to seal the disc space against flow ingestion from the main annulus. Although the sealing mass flow rate is commonly very small compared to the main annulus mass flow rate, it can have significant effects on the development of the passage endwall flows and on the overall loss generation. In this paper, the interaction between annulus and rim sealing flows is investigated using numerical simulations of a generic high-pressure turbine. At first, the numerical approach is validated by comparing the results of calculations to measurement data at the design flow conditions. Following that, results from steady and unsteady calculations are used to describe in detail the aerodynamics in overlap-type rim seals and their effects on the blade passage flow. It is found that the flow interaction at the rim seal interface is strongly influenced by the velocity deficit of the rim sealing flow relative to the annulus flow as well as by the circumferentially non-uniform pressure field imposed by the rotor blades. At typical sealing flow conditions, the flow interaction is found to be naturally unsteady, with periodical vortex shedding into the rotor passage. Finally, the influence of the specific rim seal shape on the flow unsteadiness at the rim seal interface is investigated and the impact on turbine performance is assessed.

scholarly journals Multiple Impinging Jet Air-Assisted Atomization

2017 ◽  
Author(s):  
Mário Costa ◽  
Bruno Pizziol ◽  
Miguel Panao ◽  
André Silva
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Alternative Fuels ◽  
Fossil Fuels ◽  
Cross Flow ◽  
Liquid Sheet ◽  
Air Mass ◽  
Breakup Mechanism ◽  
The Impact

The growth of the aviation sector triggered the search for alternative fuels and continued improvements in thecombustion process. This work addresses the technological challenges associated with spray systems and theconcern of mixing biofuels with fossil fuels to produce alternative and more ecological fuels for aviation. This workproposes a new injector design based on sprays produced from the simultaneous impact of multiple jets, using anadditional jet of air to assist the atomization process. The results evidence the ability to control the average dropsize through the air-mass flow rate. Depending on the air-mass flow rate there is a transition between atomizationby hydrodynamic breakup of the liquid sheet formed on the impact point, to an aerodynamic breakup mechanism,as found in the atomization of inclined jets under cross-flow conditions. The aerodynamic shear breakupdeteriorates the atomization performance, but within the same order of magnitude. Finally, our experiments showthat mixing a biofuel with a fossil fuel does not significantly alter the spray characteristics, regarded as a stepfurther in developing alternative and more ecological fuels for aero-engines.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4737

scholarly journals Importance of Communication in Law

2019 ◽  
Vol 8 (6S3) ◽  
pp. 1305-1307
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Diesel Fuel ◽  
Methyl Esters ◽  
Development Rate ◽  
Biodiesel Fuel ◽  
Gas Temperature ◽  
Warm Temperature ◽  
The Impact

The two horrible conditions ahead of time than the organizers worldwide are to diminish the stack at the conventional fills and to reduce the continually developing basic spoiling. This test is proposed to discover probably the execution of the DI diesel motor at various loads when fuelled with mixes of palm methyl esters and diesel. The primers have been pushed on a completely utilized diesel motor without changes. Every one of the appraisals were consistent usa of america and outfitted toward dependable pace. The impact of moving weight develop to be assessed the volume that brake warm temperature ability, mass flow rate, brake one of a kind gas use and fumes gas temperature. Exploratory impacts show that at complete weight conditions, the B-20, B-40and B-60 mixes bring 33.23%, 32.81%, 32.39% and 31.ninety seven% higher brake heat usefulness than sole diesel freely. It wound up confirmed that the brake warmth ability of palm biodiesel is higher than that of diesel, and it is a delayed consequence of the oxygenated atom of biodiesel which acknowledges total ingesting of the biodiesel fuel. In addition the mass development rate of biodiesel is evidently superior to anything that of diesel fuel; it is through method for exact capacity of the calorific estimation of biodiesel is a ton parcels less appeared in one another way as far as diesel gas. At the reason for results obtained from this test utilizing palm biodiesel as a fuel is proposed for the utilized as a piece of a diesel motor with diesel mixes.

scholarly journals Evaluation of Variable Compressor Technologies

2021 ◽  
Vol 6 ◽  
Author(s):  
Panagiotis Grigoriadis ◽  
Alexander Hoffmann ◽  
Chi Binh La
Keyword(s):  
Fuel Cells ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Mass ◽  
Compressor Wheel ◽  
Advantages And Disadvantages ◽  
Performance Map ◽  
Surge Line ◽  
The Impact

A diverse set of technology solutions are in development for reducing vehicular CO2 emissions. Beside the conventional internal combustion engine, there are hybrid powertrains, fuel cells and full electric vehicles. The challenge is finding the right technology that can be quickly implemented into production as a cost effective solution. In addition to CO2 reduction during vehicle operation, the impact of CO2 in the production and recycling of future vehicles must also be considered. From this perspective, the role of turbocharging is evolving, becoming more important for the future. It is an enabler for mature technologies known to improve engine efficiency like Miller timing, lean burn, increased exhaust gas recirculation (EGR) dilution and exhaust heat recovery. As a boosting device, improved turbocharging can also benefit other powertrain types like fuel cells. All previously mentioned applications benefit from wider compressor maps and higher compressor ratios. To achieve an extension of the performance map to areas of low mass flow rate, different methods have been discussed with the two most promising being trim reduction introduced by IAV’s Variable Trim Compressor (VTC) and swirl generation. The most common device for inducing a swirl onto the incoming airflow is to use swirl generating wings in front of the compressor wheel. However, Iwakiri explained that putting a single plate in front of the compressor wheel disturbs the recirculating flow, which acts positively to extend the compressor map. On this basis, plates were developed that guide the strongly swirled back flowing air in such a way that they impose a swirl on the incoming air. Trim reduction is well known for its ability to shift the surge line and maintain compressor efficiency. To achieve this, a conical element before the compressor wheel guides the incoming flow to the inner area of the wheel resulting in reduced flow separation. An orifice can also achieve almost the same effect but with much less axial extension. The advantages and disadvantages of these measures are explained using numerical (CFD) and experimental (turbocharger test bench) to show the potential of each approach. In summary trim reduction using a conical geometry is still the best performing approach. However, considering package restrictions, an orifice is also a good choice. Whereas swirl producing principles have a moderate impact on shifting the surge line. The extension of high mass flow rate is also of interest and this study shows a simple method to improve the compressor performance map in this area. A combination of the measures to expand the map in both directions is conceivable and is presented here as a concept.

On the Impact of Passive Tip-Injection on the Downstream Flow Field of a Shrouded LP-Turbine: CFD and Experimental Results

2016 ◽  
Author(s):  
Pouya Ghaffari ◽  
Reinhard Willinger
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Tip Leakage ◽  
Air Turbine ◽  
Tip Injection ◽  
Lp Turbine ◽  
Downstream Flow ◽  
The Impact ◽  
Discharge Behaviour

Using shrouded blades with fins is a common method to reduce the leakage mass flow rate through the clearance between rotor and stator. A variety of methods have been developed improving the discharge behaviour of this sealing application. The leakage mass flow rate and its interaction with the main flow resulting in mixing losses and deviations in turning is also an important issue and has to be taken into consideration. The objective of this paper is to present a method aiming at reduction of tip-leakage mass flow rate and its high angular momentum by means of passive tip-injection. The results include analytical study followed by CFD calculations for compressible flow in a rotational frame of reference as well as experimental data. An uncooled low pressure air turbine with shrouded blades is considered for the CFD and the measurements. Three passive tip-injection configurations are investigated numerically out of which one configuration is also examined experimentally in the framework of this study.

Sign in / Sign up

Export Citation Format

Share Document