DOCSLIB.ORG

Physics, Chapter 9: Hydrodynamics (Fluids in Motion)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Physics, Chapter 9: Hydrodynamics (Fluids in Motion) University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Robert Katz Publications Research Papers in Physics and Astronomy 1-1958 Physics, Chapter 9: Hydrodynamics (Fluids in Motion) Henry Semat City College of New York Robert Katz University of Nebraska-Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/physicskatz Part of the Physics Commons Semat, Henry and Katz, Robert, "Physics, Chapter 9: Hydrodynamics (Fluids in Motion)" (1958). Robert Katz Publications. 143. https://digitalcommons.unl.edu/physicskatz/143 This Article is brought to you for free and open access by the Research Papers in Physics and Astronomy at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Robert Katz Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 9 Hydrodynamics (Fluids in Motion) 9-1 Steady Flow of a Liquid When a liquid flows through a pipe in such a way that it completely fills the pipe, and as much liquid enters one end of the pipe as leaves the other end of the pipe in the same time, then the liquid is said to flow at a steady rate. At any point of the pipe, the flow of the liquid does not change with time. The path of any particle of liquid as it moves through the pipe is Fig. 9-1 Streamlines of a liquid flowing through a pipe at a steady rate. called a streamline. We can map the flow of liquid through the pipe by drawing a series of streamlines following the paths of the particles of liquid, as shown in Figure 9-1. The instantaneous velocity of a liquid particle is always tangent to the streamline. The rate of flow may be represented by the density of streamlines, or the number of streamlines passing through a surface of unit area perpendicular to the direction of flow. Thus the stream­ lines will be close together where the liquid is moving rapidly and farther apart in regions of the pipe where the liquid is moving slowly. Similar conventions were used to represent the direction and magnitude of the gravitational field intensity. Since the liquid is incompressible and there are no places in the pipe where the liquid can be stored, the volume of liquid which flows through any plane perpendicular to the streamlines in any interval of time must be the same everywhere in the pipe. Consider two typical planes whose inter­ sections with the pipe have areas Al and A 2 perpendicular to the stream- 165 166 HYDRODYNAMICS §9-1 lines. The volume of liquid Q passing through area Al in unit time is Q = AIvI, (9-1) where VI is the velocity of the liquid at this point. Similarly, the volume of liquid passing through A 2 in unit time is Q = A 2V2. Since these two quantities must be equal for steady flow, we have AIvI = A 2U2, (9-2) VI A 2 ,or -= -. V2 Al Thus the velocity of the liquid at any point in the pipe is inversely propor­ tional to the cross-sectional area of the pipe. The liquid will be moving slowly where the area is large and will be moving rapidly where the area is small. Illustrative Example. Water flows out of a horizontal pipe at the steady rate of 2 ft 3/min. Determine the velocity of the water at a point where the diameter of the pipe is I in. The area A of the I-in. portion of the pipe is A = 1r X 1 ft2 = 0.0055 ft2. 4 X 144 When we substitute the values for Q and A in Equation (9-1), 2 ft 3 we obtain -- = 0.0055 ftz X v, 60 sec ft from which v = 6.10-· sec Fig. 9-2 The number of streamlines enter­ ing a volume element is equal to the num- , bel' leaving; the volume element when there is steady flow. In the steady or streamline flow of a liquid, the total quantity of liquid flowing into any imaginary volume element of the pipe must be equal to the quantity of liquid leaving that volume element. If we represent the flow by streamlines, this implies that the streamlines are continuous and do not pile up anywhere within the liquid. The same number of streamlines enter §9-2 BERNOULLI'S THEOREM 167 a volume element as the number which leave it, as shown in Figure 9-2. Another characteristic of streamline flow is that it is layerlike, or lamellar. There is no circulation of the liquid about any point in the pipe. We might imagine a small paddle wheel, as shown in Figure 9-3, placed in the pipe. When the flow is lamellar, no rotation of the paddle wheel is produced by the flow of liquid. Fig. 9-3 A small paddle wheel placed in a flowing liquid will not rotate when the liquid is in steady or lamellar flow. .~ 9-2 Bernoulli's Theorem The fundamental theorem regarding the motion of fluids is due to Daniel Bernoulli (1700-1782), a Swiss physicist and mathematician. Bernoulli's theorem is essentially a formulation of the mechanical concept that the work done on a body is equal to the change in its mechanical energy, in the case that mechanical energy is conserved; that is, where there is no loss of mechanical energy due to friction. Let us consider the motion of an incompressible fluid of density p along an imaginary tube bounded by streamlines, as shown in Figure 9-4. We shall call such a tube a 8treamtube. Since each streamline represents the direction of motion of a particle of liquid in steady flow, no particle of liquid may cross a streamtube. At the left-hand end of the tube, the liquid has a velocity VI, the tube has cross-sectional area AI, the pressure is PI, and the tube is at a height hI above some reference level. At the right-hand end of the tube, the velocity is V2, the cross-sectional area is A 2 , the pressure is P 2 , and the height is h2 . When a small quantity of fluid of volume V is moved into the tube through the action of the external fluid, an equal volume of fluid must emerge from the streamtube against the force exerted by the pressure P 2 of the fluid outside the tube at the right-hand end of the stream­ tube. Let us imagine that the flow of fluid in the streamtube takes place as the result of the displacement 81 of a piston of area Al which just fits the streamtube at its left-hand end such that the volume swept out by the 168 HYDRODYNAMICS §9-2 motion of the piston is A1s1 V, and of a corresponding displacement S2 of a piston of area A 2 which just fits the streamtube at its right-hand end such that the volume swept out by the second piston is A 2 s2 = V; that is, a quantity of fluid of volume V has just passed through the streamtube. The piston at position 1 has done work on the fluid equal to the product of the force exerted by the displacement of that force, hence the work done on Fig. 9-4 the fluid is P1A1sl, while the fluid has pushed back the piston at position 2 so that the fluid has done work on the second piston of amount P2 A 2 s2• The net work done on the fluid is therefore equal to P1A1s1 - P2A 2 s2 . Since we have assumed the fluid to be incompressible, we have A1s1 = A 2 s2 = V. From the above equations, we find that the net work done on the fluid within the streamtube is P1V - P2 V. If there was no loss of energy of the fluid due to frictional forces, this work done on the fluid in the streamtube must have resulted in a change of mechanical energy of the liquid which flowed into the tube at position 1 and out of the tube at position 2. The sum of the potential and kinetic §9-3 TORRICELLI'S THEOREM 169 energies of the liquid flowing into the tube at position 1 is pVgh l + ! pVvi, while the sum of these energies of the liquid flowing out of the tube at positio~ 2 is pVgh2 + !pVv~. Equating the work done on the fluid to the difference in its energy, we find PIV - P 2 V = pVgh2 + !pVv~ - (pVgh l + !pVvi). (9-3a) Dividing the equation through by V and transposing all quantities with subscript 1 to the left-hand side and all quantities with subscript 2 to the right-hand side of the equation, we find PI + pgh l + !pvi = P 2 + pgh2 + !pv~. (9-3b) This equation expresses Bernoulli's theorem, which states that at any two points along a streamline the sum of the pressure, the potential energy of a unit volume of fluid, and the kinetic energy of a unit volume of fluid has the same value. As indicated in the derivation, Bernoulli's theorem holds rigorously only for frictionless, incompressible, streamline flow. Bernoulli's theorem is a statement of the principle of conservation of energy expressed in a form suited to the description of fluids in steady frictionless flow. Although Bernoulli's theorem holds rigorously only for an incompres­ sible fluid, experience indicates that it is valid for air in streamline flow at speeds up to about half the speed of sound. (The speed of sound is about 740 mijhr.) Actual fluids such as water and air have internal fluid friction, or viscosity, so that, to be strictly true, the equal sign of Equation (9-3a) should be replaced by a greater than or equal sign (~), meaning that the work done on the fluid in the streamtube is greater than, or at least equal to, the increase in mechanical energy.
Load more

Recommended publications
  • Glossary Physics (I-Introduction)
    1 Glossary Physics (I-introduction) - Efficiency: The percent of the work put into a machine that is converted into useful work output; = work done / energy used [-]. = eta In machines: The work output of any machine cannot exceed the work input (<=100%); in an ideal machine, where no energy is transformed into heat: work(input) = work(output), =100%. Energy: The property of a system that enables it to do work. Conservation o. E.: Energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes. Equilibrium: The state of an object when not acted upon by a net force or net torque; an object in equilibrium may be at rest or moving at uniform velocity - not accelerating. Mechanical E.: The state of an object or system of objects for which any impressed forces cancels to zero and no acceleration occurs. Dynamic E.: Object is moving without experiencing acceleration. Static E.: Object is at rest.F Force: The influence that can cause an object to be accelerated or retarded; is always in the direction of the net force, hence a vector quantity; the four elementary forces are: Electromagnetic F.: Is an attraction or repulsion G, gravit. const.6.672E-11[Nm2/kg2] between electric charges: d, distance [m] 2 2 2 2 F = 1/(40) (q1q2/d ) [(CC/m )(Nm /C )] = [N] m,M, mass [kg] Gravitational F.: Is a mutual attraction between all masses: q, charge [As] [C] 2 2 2 2 F = GmM/d [Nm /kg kg 1/m ] = [N] 0, dielectric constant Strong F.: (nuclear force) Acts within the nuclei of atoms: 8.854E-12 [C2/Nm2] [F/m] 2 2 2 2 2 F = 1/(40) (e /d ) [(CC/m )(Nm /C )] = [N] , 3.14 [-] Weak F.: Manifests itself in special reactions among elementary e, 1.60210 E-19 [As] [C] particles, such as the reaction that occur in radioactive decay.
    [Show full text]
  • Equation of State for the Lennard-Jones Fluid
    Equation of State for the Lennard-Jones Fluid Monika Thol1*, Gabor Rutkai2, Andreas Köster2, Rolf Lustig3, Roland Span1, Jadran Vrabec2 1Lehrstuhl für Thermodynamik, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany 2Lehrstuhl für Thermodynamik und Energietechnik, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany 3Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, Ohio 44115, USA Abstract An empirical equation of state correlation is proposed for the Lennard-Jones model fluid. The equation in terms of the Helmholtz energy is based on a large molecular simulation data set and thermal virial coefficients. The underlying data set consists of directly simulated residual Helmholtz energy derivatives with respect to temperature and density in the canonical ensemble. Using these data introduces a new methodology for developing equations of state from molecular simulation data. The correlation is valid for temperatures 0.5 < T/Tc < 7 and pressures up to p/pc = 500. Extensive comparisons to simulation data from the literature are made. The accuracy and extrapolation behavior is better than for existing equations of state. Key words: equation of state, Helmholtz energy, Lennard-Jones model fluid, molecular simulation, thermodynamic properties _____________ *E-mail: [email protected] Content Content ....................................................................................................................................... 2 List of Tables .............................................................................................................................
    [Show full text]
  • Viscosity of Gases References
    VISCOSITY OF GASES Marcia L. Huber and Allan H. Harvey The following table gives the viscosity of some common gases generally less than 2% . Uncertainties for the viscosities of gases in as a function of temperature . Unless otherwise noted, the viscosity this table are generally less than 3%; uncertainty information on values refer to a pressure of 100 kPa (1 bar) . The notation P = 0 specific fluids can be found in the references . Viscosity is given in indicates that the low-pressure limiting value is given . The dif- units of μPa s; note that 1 μPa s = 10–5 poise . Substances are listed ference between the viscosity at 100 kPa and the limiting value is in the modified Hill order (see Introduction) . Viscosity in μPa s 100 K 200 K 300 K 400 K 500 K 600 K Ref. Air 7 .1 13 .3 18 .5 23 .1 27 .1 30 .8 1 Ar Argon (P = 0) 8 .1 15 .9 22 .7 28 .6 33 .9 38 .8 2, 3*, 4* BF3 Boron trifluoride 12 .3 17 .1 21 .7 26 .1 30 .2 5 ClH Hydrogen chloride 14 .6 19 .7 24 .3 5 F6S Sulfur hexafluoride (P = 0) 15 .3 19 .7 23 .8 27 .6 6 H2 Normal hydrogen (P = 0) 4 .1 6 .8 8 .9 10 .9 12 .8 14 .5 3*, 7 D2 Deuterium (P = 0) 5 .9 9 .6 12 .6 15 .4 17 .9 20 .3 8 H2O Water (P = 0) 9 .8 13 .4 17 .3 21 .4 9 D2O Deuterium oxide (P = 0) 10 .2 13 .7 17 .8 22 .0 10 H2S Hydrogen sulfide 12 .5 16 .9 21 .2 25 .4 11 H3N Ammonia 10 .2 14 .0 17 .9 21 .7 12 He Helium (P = 0) 9 .6 15 .1 19 .9 24 .3 28 .3 32 .2 13 Kr Krypton (P = 0) 17 .4 25 .5 32 .9 39 .6 45 .8 14 NO Nitric oxide 13 .8 19 .2 23 .8 28 .0 31 .9 5 N2 Nitrogen 7 .0 12 .9 17 .9 22 .2 26 .1 29 .6 1, 15* N2O Nitrous
    [Show full text]
  • On Nonlinear Strain Theory for a Viscoelastic Material Model and Its Implications for Calving of Ice Shelves
    Journal of Glaciology (2019), 65(250) 212–224 doi: 10.1017/jog.2018.107 © The Author(s) 2019. This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives licence (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is unaltered and is properly cited. The written permission of Cambridge University Press must be obtained for commercial re- use or in order to create a derivative work. On nonlinear strain theory for a viscoelastic material model and its implications for calving of ice shelves JULIA CHRISTMANN,1,2 RALF MÜLLER,2 ANGELIKA HUMBERT1,3 1Division of Geosciences/Glaciology, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany 2Institute of Applied Mechanics, University of Kaiserslautern, Kaiserslautern, Germany 3Division of Geosciences, University of Bremen, Bremen, Germany Correspondence: Julia Christmann <[email protected]> ABSTRACT. In the current ice-sheet models calving of ice shelves is based on phenomenological approaches. To obtain physics-based calving criteria, a viscoelastic Maxwell model is required account- ing for short-term elastic and long-term viscous deformation. On timescales of months to years between calving events, as well as on long timescales with several subsequent iceberg break-offs, deformations are no longer small and linearized strain measures cannot be used. We present a finite deformation framework of viscoelasticity and extend this model by a nonlinear Glen-type viscosity. A finite element implementation is used to compute stress and strain states in the vicinity of the ice-shelf calving front.
    [Show full text]
  • 1 Fluid Flow Outline Fundamentals of Rheology
    Fluid Flow Outline • Fundamentals and applications of rheology • Shear stress and shear rate • Viscosity and types of viscometers • Rheological classification of fluids • Apparent viscosity • Effect of temperature on viscosity • Reynolds number and types of flow • Flow in a pipe • Volumetric and mass flow rate • Friction factor (in straight pipe), friction coefficient (for fittings, expansion, contraction), pressure drop, energy loss • Pumping requirements (overcoming friction, potential energy, kinetic energy, pressure energy differences) 2 Fundamentals of Rheology • Rheology is the science of deformation and flow – The forces involved could be tensile, compressive, shear or bulk (uniform external pressure) • Food rheology is the material science of food – This can involve fluid or semi-solid foods • A rheometer is used to determine rheological properties (how a material flows under different conditions) – Viscometers are a sub-set of rheometers 3 1 Applications of Rheology • Process engineering calculations – Pumping requirements, extrusion, mixing, heat transfer, homogenization, spray coating • Determination of ingredient functionality – Consistency, stickiness etc. • Quality control of ingredients or final product – By measurement of viscosity, compressive strength etc. • Determination of shelf life – By determining changes in texture • Correlations to sensory tests – Mouthfeel 4 Stress and Strain • Stress: Force per unit area (Units: N/m2 or Pa) • Strain: (Change in dimension)/(Original dimension) (Units: None) • Strain rate: Rate
    [Show full text]
  • Chapter 3 Equations of State
    Chapter 3 Equations of State The simplest way to derive the Helmholtz function of a fluid is to directly integrate the equation of state with respect to volume (Sadus, 1992a, 1994). An equation of state can be applied to either vapour-liquid or supercritical phenomena without any conceptual difficulties. Therefore, in addition to liquid-liquid and vapour -liquid properties, it is also possible to determine transitions between these phenomena from the same inputs. All of the physical properties of the fluid except ideal gas are also simultaneously calculated. Many equations of state have been proposed in the literature with either an empirical, semi- empirical or theoretical basis. Comprehensive reviews can be found in the works of Martin (1979), Gubbins (1983), Anderko (1990), Sandler (1994), Economou and Donohue (1996), Wei and Sadus (2000) and Sengers et al. (2000). The van der Waals equation of state (1873) was the first equation to predict vapour-liquid coexistence. Later, the Redlich-Kwong equation of state (Redlich and Kwong, 1949) improved the accuracy of the van der Waals equation by proposing a temperature dependence for the attractive term. Soave (1972) and Peng and Robinson (1976) proposed additional modifications of the Redlich-Kwong equation to more accurately predict the vapour pressure, liquid density, and equilibria ratios. Guggenheim (1965) and Carnahan and Starling (1969) modified the repulsive term of van der Waals equation of state and obtained more accurate expressions for hard sphere systems. Christoforakos and Franck (1986) modified both the attractive and repulsive terms of van der Waals equation of state. Boublik (1981) extended the Carnahan-Starling hard sphere term to obtain an accurate equation for hard convex geometries.
    [Show full text]
  • Two-Way Fluid–Solid Interaction Analysis for a Horizontal Axis Marine Current Turbine with LES
    water Article Two-Way Fluid–Solid Interaction Analysis for a Horizontal Axis Marine Current Turbine with LES Jintong Gu 1,2, Fulin Cai 1,*, Norbert Müller 2, Yuquan Zhang 3 and Huixiang Chen 2,4 1 College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China; [email protected] 2 Department of Mechanical Engineering, Michigan State University, East Lansing, MI 48824, USA; [email protected] (N.M.); [email protected] (H.C.) 3 College of Energy and Electrical Engineering, Hohai University, Nanjing 210098, China; [email protected] 4 College of Agricultural Engineering, Hohai University, Nanjing 210098, China * Correspondence: fl[email protected]; Tel.: +86-139-5195-1792 Received: 2 September 2019; Accepted: 23 December 2019; Published: 27 December 2019 Abstract: Operating in the harsh marine environment, fluctuating loads due to the surrounding turbulence are important for fatigue analysis of marine current turbines (MCTs). The large eddy simulation (LES) method was implemented to analyze the two-way fluid–solid interaction (FSI) for an MCT. The objective was to afford insights into the hydrodynamics near the rotor and in the wake, the deformation of rotor blades, and the interaction between the solid and fluid field. The numerical fluid simulation results showed good agreement with the experimental data and the influence of the support on the power coefficient and blade vibration. The impact of the blade displacement on the MCT performance was quantitatively analyzed. Besides the root, the highest stress was located near the middle of the blade. The findings can inform the design of MCTs for enhancing robustness and survivability.
    [Show full text]
  • Guide to Rheological Nomenclature: Measurements in Ceramic Particulate Systems
    NfST Nisr National institute of Standards and Technology Technology Administration, U.S. Department of Commerce NIST Special Publication 946 Guide to Rheological Nomenclature: Measurements in Ceramic Particulate Systems Vincent A. Hackley and Chiara F. Ferraris rhe National Institute of Standards and Technology was established in 1988 by Congress to "assist industry in the development of technology . needed to improve product quality, to modernize manufacturing processes, to ensure product reliability . and to facilitate rapid commercialization ... of products based on new scientific discoveries." NIST, originally founded as the National Bureau of Standards in 1901, works to strengthen U.S. industry's competitiveness; advance science and engineering; and improve public health, safety, and the environment. One of the agency's basic functions is to develop, maintain, and retain custody of the national standards of measurement, and provide the means and methods for comparing standards used in science, engineering, manufacturing, commerce, industry, and education with the standards adopted or recognized by the Federal Government. As an agency of the U.S. Commerce Department's Technology Administration, NIST conducts basic and applied research in the physical sciences and engineering, and develops measurement techniques, test methods, standards, and related services. The Institute does generic and precompetitive work on new and advanced technologies. NIST's research facilities are located at Gaithersburg, MD 20899, and at Boulder, CO 80303.
    [Show full text]
  • Navier-Stokes Equations Some Background
    Navier-Stokes Equations Some background: Claude-Louis Navier was a French engineer and physicist who specialized in mechanics Navier formulated the general theory of elasticity in a mathematically usable form (1821), making it available to the field of construction with sufficient accuracy for the first time. In 1819 he succeeded in determining the zero line of mechanical stress, finally correcting Galileo Galilei's incorrect results, and in 1826 he established the elastic modulus as a property of materials independent of the second moment of area. Navier is therefore often considered to be the founder of modern structural analysis. His major contribution however remains the Navier–Stokes equations (1822), central to fluid mechanics. His name is one of the 72 names inscribed on the Eiffel Tower Sir George Gabriel Stokes was an Irish physicist and mathematician. Born in Ireland, Stokes spent all of his career at the University of Cambridge, where he served as Lucasian Professor of Mathematics from 1849 until his death in 1903. In physics, Stokes made seminal contributions to fluid dynamics (including the Navier–Stokes equations) and to physical optics. In mathematics he formulated the first version of what is now known as Stokes's theorem and contributed to the theory of asymptotic expansions. He served as secretary, then president, of the Royal Society of London The stokes, a unit of kinematic viscosity, is named after him. Navier Stokes Equation: the simplest form, where is the fluid velocity vector, is the fluid pressure, and is the fluid density, is the kinematic viscosity, and ∇2 is the Laplacian operator.
    [Show full text]
  • Hydraulics Manual Glossary G - 3
    Glossary G - 1 GLOSSARY OF HIGHWAY-RELATED DRAINAGE TERMS (Reprinted from the 1999 edition of the American Association of State Highway and Transportation Officials Model Drainage Manual) G.1 Introduction This Glossary is divided into three parts: · Introduction, · Glossary, and · References. It is not intended that all the terms in this Glossary be rigorously accurate or complete. Realistically, this is impossible. Depending on the circumstance, a particular term may have several meanings; this can never change. The primary purpose of this Glossary is to define the terms found in the Highway Drainage Guidelines and Model Drainage Manual in a manner that makes them easier to interpret and understand. A lesser purpose is to provide a compendium of terms that will be useful for both the novice as well as the more experienced hydraulics engineer. This Glossary may also help those who are unfamiliar with highway drainage design to become more understanding and appreciative of this complex science as well as facilitate communication between the highway hydraulics engineer and others. Where readily available, the source of a definition has been referenced. For clarity or format purposes, cited definitions may have some additional verbiage contained in double brackets [ ]. Conversely, three “dots” (...) are used to indicate where some parts of a cited definition were eliminated. Also, as might be expected, different sources were found to use different hyphenation and terminology practices for the same words. Insignificant changes in this regard were made to some cited references and elsewhere to gain uniformity for the terms contained in this Glossary: as an example, “groundwater” vice “ground-water” or “ground water,” and “cross section area” vice “cross-sectional area.” Cited definitions were taken primarily from two sources: W.B.
    [Show full text]
  • Frequently Asked Questions
    FREQUENTLY ASKED QUESTIONS Pressure Washer Chemicals/Cleaners Q: Can I use chemicals that do not state pressure washer safe? Can I use bleach in my pressure washer? A: It is recommended that only cleaning products that state "pressure washer safe" be used. Please ensure to follow all of the manufacturer's instructions. Using bleach or any other chemicals/cleaners that do not state "pressure washer safe" can cause premature wear and damage to seals and o-rings. Continuous Water Source Requirement for Pressure Washers Q: Does my pressure washer require a continuous water source? A: Pressure washers require a continuous pressurized water source. If there is not adequate water to the pump, the unit will not operate correctly and the pump may sustain damage. Please check your Operator's Manual for the specific requirements of gallons per minute and psi for your unit. Pressure Washer Siphon Troubleshooting Q: How do I get the pressure washer to siphon? A: For basic operating instructions related to your specific pressure washer, please refer to your product Owner's Manual. Possible causes for lack of siphoning include: • Chemical hose placed on improper port -- Check clear hose placement. • Pressure washer is not set to low pressure --The unit must be set to low pressure to apply soap. Please be sure that the correct soap nozzle is being used. • Extension is being used on the high pressure hose -- Remove extension on high pressure hose. • Chemical injection area is clogged or component needs to be replaced -- Test for blockage: Remove nozzle extension from gun, attach and turn on water source, then pull the trigger.
    [Show full text]
  • Application Note to the Field Pumping Non-Newtonian Fluids with Liquiflo Gear Pumps
    Pumping Non-Newtonian Fluids Application Note to the Field with Liquiflo Gear Pumps Application Note Number: 0104-2 Date: April 10, 2001; Revised Jan. 2016 Newtonian vs. non-Newtonian Fluids: Fluids fall into one of two categories: Newtonian or non-Newtonian. A Newtonian fluid has a constant viscosity at a particular temperature and pressure and is independent of shear rate. A non-Newtonian fluid has viscosity that varies with shear rate. The apparent viscosity is a measure of the resistance to flow of a non-Newtonian fluid at a given temperature, pressure and shear rate. Newton’s Law states that shear stress () is equal the dynamic viscosity () multiplied by the shear rate (): = . A fluid which obeys this relationship, where is constant, is called a Newtonian fluid. Therefore, for a Newtonian fluid, shear stress is directly proportional to shear rate. If however, varies as a function of shear rate, the fluid is non-Newtonian. In the SI system, the unit of shear stress is pascals (Pa = N/m2), the unit of shear rate is hertz or reciprocal seconds (Hz = 1/s), and the unit of dynamic viscosity is pascal-seconds (Pa-s). In the cgs system, the unit of shear stress is dynes per square centimeter (dyn/cm2), the unit of shear rate is again hertz or reciprocal seconds, and the unit of dynamic viscosity is poises (P = dyn-s-cm-2). To convert the viscosity units from one system to another, the following relationship is used: 1 cP = 1 mPa-s. Pump shaft speed is normally measured in RPM (rev/min).
    [Show full text]