Pipeline Hydraulics Design Basis Engineering Essay

call tilt Hydraulics objective Basis Engineering EssayIt intromits the electron tube and f grim characteristics of the transported gas on a lower floor specified operating conditions as established in the design basis. swiftnessThe tubing up upline has to be laid for the outer space of 770km in the midst of Portland and Montreal, the fluid in the pipe is Light Crude Oil. focal proportion of proceed in a line of reasoning is the average pep pill based on the pipe diameter and bland menstruation drift. Its selection is first step in the plan procedure of our project. The issue speed female genital organ save both advantages and drawbacks. high-pitched velocities can ca phthisis turbulence, and the striking of the fluid on the walls of the pipe which testament cause damage to the pipes and eventually erode away the pipe, while low velocity on the other hand can cause the sediment of particulates in the line and cleanliness of the fluid lead be compromised. Ther efore, to avoid these problems liquifiable lines atomic weigh 18 normally sized to maintain a velocity sufficient to confine the solid particles from depositing and also to prevent the erosion of the pipe. Under these considerations the recommended velocity is in the vagabond of 3ft/s to 8ft/s.From this selected range of velocity we have to select a single velocity. The velocity we have selected for our line is 5ft/s. This is the intermediate velocity from the recommended range and all the further calculations will be done on this velocity.Velocity SelectionThe range as mentioned in a higher place is taken as 3ft/s to 5ft/s. The next step is to select a single velocity from this range. We have selected 5ft/s for our line. The reason for this velocity selection is the trade-off between pipe diameter and look of heart and soul displace. According to continuity comparison if we increase the velocity, the corresponding diameter will burn but the obligate issue will increas e receivable to which a higher trope of pump stations are required. Similarly if we decrease the velocity, the estimate of pump stations will reduce but the diameter will increase for a habituated time period rate. Since the pipeline is laid over a big distance, the pipeline cost holds the study share of the capital investment so increasing the diameter will adversely affect the economics of pipeline. This trade-off is visible in the calculations shown in appendix A.The other reason for choosing this velocity is that if the execute rate fluctuates in the future for any reason the diameter selected from this intermediate velocity will be able to accommodate those variations with knocked out(p) affecting our system.Diameter CalculationCalculation of the diameter is the core of the hydraulic designing.The diameter selected should be able to support the stresses on the pipe, the capacity of the fluid and lessen the bosom losings.Under given move rate and assumed velocities, we can look the pipe diameter apply continuity equivalenceV=Q/AV cling velocityQ Volume guide rateA Cross sectional areaThe flow rate is given as 109,000bbl/ solar day or 7.1ft3/s. The diameters are directd at 3, 4, 5ft/s velocities and the respective diameters are 20.83, 18.04 and 16.14.Selection of DiameterAs mentioned above 5ft/s is selected as the recommended velocity and the corresponding home(a) diameter (ID) is 16.14in. nominated subway system SizeFor the inner(a) diameter subsequently we have to rate the nominal pipe size. To calculate the nominal diameter we refer to the thermionic valve Data provided for the Carbon Steel. From the table shown in appendix B, it is found out that consequent nominal pipe size will be 18in.Characteristics of pointDifferent flow properties are deliberate to determine the regime of flow, outletes in the pipes.The nature of the flow can be bedded or churning.There are two graphic symbols of the dismissales. Major losses include the losses due to corrasion in neat pipes and minor losses due to bends, valves, tees.To calculate these we will be dealing with Reynolds result (for nature of flow), morose plat (for corrasion reckon) and transport loss calculations. lossesAs the fluid flows by the pipe there is friction at the pipe wall and fluid interface in the straight portions of the pipe due to interference between the fluid and the walls of the pipe. This friction closures in results in the loss of energy in the lineat the expense of liquid hale and the losses are known as the major losses. scream systems consist of components in addition to straight pipes. These include bends, valves, tees etc and add further to the losses in the line. These losses are termed as minor losses.Experimental data is used to calculate these losses as the a priori prediction is complex.Major LossesThe pressure drop due to friction in a pipeline depends on the flow rate, pipe diameter, pipe cruelness, liquid particul ar(prenominal) gravity, and viscosity. In addition, the frictional pressure drop depends on the Reynolds number (and hence the flow regime). Therefore, the fluid in the pipeline will undergo pressure losses as it runs in the line and reduce the operating pressure. This loss needs to be recovered and to maintain the pressure pumps are installed at specific locations according to the requirement (pumps are discussed in Chapter ahead). These pressure losses are calculated by using the Darcy-Weisbach decreeP = f(L/D)(V2/2)Where,f=Darcy friction reckon, dimensionless, usually a number between 0.008 and 0.10L=Pipe length, ftD=Pipe ingrained diameter, ftThe pressure loss for velocity of 5ft/s comes out to be 9625.15psi. All the relevant calculations are shown in appendix A.Minor LossesReal pipeline systems mostly consist of more than straight pipes. The redundant components (valves, tees and bends) add to the overall loss of the system. These are termed as minor losses. In shell of p recise long pipes, these losses are usually undistinguished incomparison to thefluid friction in the length considered. however in caseof short pipes,these minor losses may actually be major losses such as insuction pipe of a pumpwith strainer and foot valves.These losses represent additional energy dissipation in the flow, usually caused by secondary flows induced by curvature or recirculation.Minor loss in diverging flow is much larger than thatin converging flow. Minor lossesgenerally increase with an increase in the geometrical distortion of the flow. Thoughminor losses are usually confined to a veryshort length of path, the opinions maynotdisappear for a considerable distance downstream. Itis insignificant in case oflaminar flow.The pressure drop by dint of valves and fittings is generallyexpressed in terms of the liquid kinetic energy V2/2g multiplied by a head loss coefficient K. Comparing this with the Darcy-Weisbach equation for head loss in a pipe, we can see the foll owing analogy. For a straight pipe, the head loss h is V2/2g multiplied by the factor (fL/D). Thus, the head loss coefficient for a straight pipe is fL/D.Therefore, the pressure drop in a valve or fitting is calculated as followsh=K(V2)/2gWhere,h= calculate loss due to valve or fitting, ftK=Head loss coefficient for the valve or fitting, dimensionlessV=Velocity of liquid by dint of valve or fitting, ft/sg=Acceleration due to gravity, 32.2 ft/s2 in English unitsThe head loss coefficient K is, for a given flow geometry, considered practically constant at high Reynolds number. K increases with pipe aroundness and with lower Reynolds numbers. In general the value of K is determined mainly by the flow geometry or by the shape of the pressureloss device.Minor loss is generally expressed in one ofthe two waysIn terms of minor loss factor K.In terms length, combining weight to acertain length of straight pipe, usuallyexpressed in terms of number of pipe diameter.The minor losses for our system are calculated and result in a very low value and can comfortably be neglected.Reynolds NumberFlow in a liquid pipeline may be smooth, laminar flow, also known as saccharine or streamline flow. In this type of flow the liquid flows in layers or laminations without causing eddies or turbulence. But as the velocity increases the flow changes from laminar to turbulent with eddies and turbulences. The important parameter used in classifying the type of flow in the pipe is called Reynolds Number.Reynolds number gives us the ratio of inertial forces to viscous forces and is used to determine the nature of flow using the recommended velocity and the internal diameter. Reynolds number is given byRe = VD/Flow through pipes is classified into three main flow regimes and depending upon the Reynolds number, flow through pipes will fall in one of the following three flow regimes.1. Laminar flow R2. Critical flow R2000 and R3. degraded flow R4000Friction FactorFriction Factor is a dimen sionless number required to calculate the pressure losses in the pipe. Tests have shown that f is dependent upon Reynolds number and relative roughness of the pipe. Relative roughness is ratio of absolute pipe wall roughness to the pipe diameter D.For laminar flow, with Reynolds number Rf=64/RFor laminar flow the friction factor depends besides on the Reynolds number and is independent of the internal condition of the pipe. Thus, regardless of whether the pipe is smooth or rough, the friction factor for laminar flow is a number that varies inversely with the Reynolds number.For turbulent flow, when the Reynolds number R4000, the friction factor f depends not only on R but also on the internal roughness of the pipe. As the pipe roughness increases, so does the friction factor. Therefore, smooth pipes have a smaller friction factor compared with rough pipes. More importantly, friction factor depends on the relative roughness (/D) rather than the absolute pipe roughness .In the turb ulent neck of the woods it can be calculated using all the Colebrook-White equation or the morose Diagram.Colebrook-White EquationThe Colebrook equation is an implicit equation that combines experimental results of studies of turbulent flow in smooth and rough pipe The Colebrook equation is given as1/f = -2log((/3.7D)+(2.51/Ref))But the turbulent flow region (R4000) consists of three separate regionsTurbulent flow in smooth pipesTurbulent flow in fully rough pipesTransition flow between smooth and rough pipesFor turbulent flow in smooth pipes, pipe roughness has a negligible effect on the friction factor. Therefore, the friction factor in this region depends only on the Reynolds number as follows1/f = -2log(2.51/Ref)For turbulent flow in fully rough pipes, the friction factor f appears to be less dependent on the Reynolds number as the last mentioned increases in magnitude. It depends only on the pipe roughness and diameter. It can be calculated from the following equation1/f = -2log((/3.7D)For the transition region between turbulent flow in smooth pipes and turbulent flow in fully rough pipes, the friction factor f is calculated using the Colebrook-White equation given above1/f = -2log((/3.7D)+(2.51/Ref))Moody DiagramThe Colebrook equation is an implicit equation and requires trial and actus reus method to calculate f.To provide the ease for calculating f scientists and researchers highly-developed a graphical method known as Moody diagram.The Moody chart or Moody diagramis a graph that relates the friction factor, Reynolds number and relative roughness for fully developed flow in a circular pipe.In the diagram friction factor is plot verses Reynolds number. The curves are plotted using the experimental data. The Moody diagram represents the complete friction factor map for laminar and all turbulent regions of pipe flows.To use the Moody diagram for determining the friction factor f we first calculate the Reynolds number R for the flow. Next, we find the location on the horizontal bloc of Reynolds number for the value of R and draw a vertical line that intersects with the appropriate relative roughness (e/D) curve. From this point of intersection on the (e/D) curve, we drive the value of the friction factor f on the vertical bloc on the left.Other Pressure Drop RelationsHazen-Williams EquationThe Hazen-Williams equation is commonly used in the design of waterdistribution lines and in the calculation of frictional pressure drop inrefined petroleum products such as gasoline and diesel. This methodinvolves the use of the Hazen-Williams C-factor instead of pipe roughnessor liquid viscosity. The pressure drop calculation using the Hazen-Williams equation takes into account flow rate, pipe diameter, and specificgravity as followsh=4.73L(Q/C)1.852/D4.87Where,h=Head loss due to friction, ftL=Pipe length, ftD=Pipe internal diameter, ftQ=Flow rate, ft3/sC=Hazen-Williams coefficient or C-factor, dimensionlessIn customary pipeline units, th e Hazen-Williams equation can berewritten as follows in English unitsQ=0.1482(C)(D)2.63 (Pm/Sg)0.54Where,Q=Flow rate, bbl/dayD=Pipe internal diameter, in.Pm=Frictional pressure drop, psi/mileSg= legato specific gravityAnother form of Hazen-Williams equation, when the flow rate is in gal/ min and head loss is measured in feet of liquid per thousand feet of pipe is as followsGPM=6.7547-10-3(C)(D)2.63(HL)0.54Where,GPM=Flow rate, gal/minHL=Friction loss, ft of liquid per 1000 ft of pipeIn SI units, the Hazen-Williams equation is as followsQ=9.0379-10-8(C)(D)2.63(Pkm/Sg)0.54Where,Q=Flow rate, m3/hrD=Pipe internal diameter, mmPkm=Frictional pressure drop, kPa/kmSg= silver-tongued specific gravityShell-MIT EquationThe Shell-MIT equation, sometimes called the MIT equation, is used in the calculation of pressure drop in heavy crude oil and heated liquid pipelines. Using this method, a modified Reynolds number Rm iscalculated first from the Reynolds number as followsR=92.24(Q)/(D)Rm=R/(7742)W here,R=Reynolds number, dimensionlessRm=Modified Reynolds number, dimensionlessQ=Flow rate, bbl/dayD=Pipe internal diameter, in.=Kinematic viscosity, cStThan depending on the flow (laminar or turbulent), the friction factor is calculated from one of the following equationsf=0.00207/Rm (laminar flow)f=0.0018+0.00662(1/Rm)0.355 (turbulent flow)Finally, the pressure drop due to friction is calculated using theequationPm=0.241(f SgQ2)/D5Where,Pm=Frictional pressure drop, psi/milef=Friction factor, dimensionlessSg= swimming specific gravityQ=Flow rate, bbl/dayD=Pipe internal diameter, in.In SI units the MIT equation is expressed as followsPm=6.2191-1010(f SgQ2)/D5Where,Pm=Frictional pressure drop, kPa/kmf=Friction factor, dimensionlessSg=Liquid specific gravityQ=Flow rate, m3/hrD=Pipe internal diameter, mm