Feasibility of direct pumping for irrigation improvement projects

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  • 1. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME494FEASIBILITY OF DIRECT PUMPING FOR IRRIGATIONIMPROVEMENT PROJECTSIbrahim R. Teaima1, Alaa A. A. Gharieb2and M. A. Younes11Mechanical and Electrical Research Institute, National Water Research Center, DeltaBarrage, Egypt2Water Management Research Institute, National Water Research Center, Delta Barrage,EgyptABSTRACTThis research was initiated with the objective of studying the feasibility of replacingthe head tank as a safety system feeder at the irrigation pipeline with air valve in order toreduce the cost of meska improvement per feddan. Field measurements were conducted onthree mesqa pumping stations at Meet Yazid command area. A numerical simulation to thepressure variation for unsteady state flow was performed using KY Pipe 2010 code. Pressurehistory during power failure was presented. A comparison between the computation and fieldmeasurements was held. The comparison indicated that the numerical simulations were ingood agreement with actual field measurements values. The research indicated that the headtank, at the pumping station, could be replaced with an air valve without any dangerous effectand might save about 606 LE/feddan.Keywords: Irrigation improvement, direct pumping, pipeline safety, head tank.1. INTRODUCTIONImprovement of tertiary canals (meska) constitutes the major part of improvingirrigation performance. It includes replacement of the existing system with improved ones.The old system is usually earthen and low level ditch with non-organized water withdrawalthrough multiple pumping/lifting points along its length. Two types were recommended forimproving the old system, open elevated mesqa and buried low-pressure pipe. Elevated one isan open ditch, but lined and elevated. Normal water level in the elevated mesqa was set toINTERNATIONAL JOURNAL OF MECHANICAL ENGINEERINGAND TECHNOLOGY (IJMET)ISSN 0976 – 6340 (Print)ISSN 0976 – 6359 (Online)Volume 4, Issue 2, March - April (2013), pp. 494-511© IAEME: www.iaeme.com/ijmet.aspJournal Impact Factor (2013): 5.7731 (Calculated by GISI)www.jifactor.comIJMET© I A E M E
  • 2. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME495permit gravity flow to fields at 15 cm above the level. Alternatives for elevated mesqainclude a rectangular concrete cast-in place selection and pre-cast concrete “J” section. Lowpressure PVC pipeline mesqa is another option for replacing the old mesqa. It is set atapproximately one meter below grad and is provided with risers at spacing of 100 meters.Such types of mesqas, elevated or pipeline are intended to reduce the seepage of water tominimum value.This research was initiated with the objective of studying the feasibility of replacing the headtank as a safety system feeder at the irrigation pipeline with air valve in order to reduce thecost of meska improvement per feddan.The investigation phases during the course of this research are presented in this paper underthe following headlines:• Outlining Irrigation Improvement Project (IIP)• Describing the study area• Outlining the pumping system within the study area• Describing the hydraulic transient• Executing simulations• Executing field measurements• Analyzing and presenting the results• Comparing the field and numerical results• Undergoing a financial and an economic analyses:2. OUTLINING THE IRRIGATION IMPROVEMENT PROJECT (IIP)The Irrigation Improvement Project (IIP) is a project which is implemented in order toincrease water use efficiency and agricultural productivity in Egypt’s old lands. Increasingwater use efficiency is used in a broad sense with a connotation of improving irrigation watermanagement rather than in the sense of the traditional definitions of water use efficiency, thisis to be accomplished by implementing a series of interventions at the irrigation deliverysystem and on-farm levels, designed to remove irrigation related constraints to increasedagricultural production and to consider a full range of technical, economic, environmentaland social factors impacting irrigation water management. The IIP package includes bothhard and soft interventions at the delivery and tertiary (meska) system levels. Hardwareinterventions at the meska level comprise the construction of collective pumping stations(single-point lifting) at the head of each meska and replacing the old earth meskas with eitherlined sections (prefabricated “J” sections) or low pressure buried pipelines with alfalfa valves.More than 2200 new meskas have been constructed so far, all meskas are equipped withdiesel pumping stations.The general layout of the systems is similar. It comprise from a small pumping station,a head tank (a stand), and a pipeline (Mesqa) up to a bout 2000 m long at the end of which isa vent/surge stand pipe, figure (1). This pipeline is composed of PVC pipe with diameters of315-450 mm. The pipeline has outlets at intervals along it which serve quaternary units(Marwas). Each outlet has a screw down valve allowing water to be discharged into openchannels.
  • 3. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME496Figure (1) General layout of the meska pumping stationIrrigation Improvement Project (IIP) was one of two schemes to achieve irrigationimprovement. IIP is made up of improved control structures using modern methods in landleveling/tillage, on-farm development, rehabilitation of main and branch canals and most ofall mesqas (using pipeline mesqa instead of earth mesqa), promoting equity of waterdistribution, and attaining a form of cooperation between the irrigation directorate andfarmers by forming water users associations [1]. The Egyptian government is planning tocontinue the improvement works to reach a target of more than 3 million feddan by the year2017 [2], [3] and [4]. IIP project has interesting impacts on the improved irrigation systemthrough increasing crop yield, land area and other variable impacts [5], [6] and [7]. IntegratedIrrigation Improvement and Management Project, (IIIMP) was the second scheme to achieveoptimal water resources use. The impacts of IIIMP is expected to achieve additional positiveeffects on water distribution, quantity, quality, equity, timeliness, water saving by usingpipeline marwa instead of existing earth cross section and other technical assistance requiredfor establishing water boards and water user associations [8].The existing pumping stations with head tank as shown in figure (2) in addition,future IIP projects are currently under preparation to bring more areas under improvement.The contribution of pipeline cost, pumping station, civil work cost, pump sets cost andbackfilling cost on the total cost are 47%, 29%, 14% and 10% respectively [9]. It means thatthe main affective items on the total cost are the pipeline, pumping station and civil works.The cost of the head tank is the major element which affects civil works.
  • 4. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME497Figure (2) Existing pumping station with head tankEl-Askari et.al [10] studied the technical, economic and social feasibilities of electrifying thepumping stations of the improved meskas in future IIP projects instead of using dieselpumping sets.3. DESCRIBING THE STUDY AREAA study area was chosen to be investigated. This area is about 105,325 feddans withinMeet Yazid Canal command area. The area belongs to Gharbia and Kafr El-SheikhDirectorates in the Nile Delta and is located adjacent to existing IIP areas.Slightly more than 500 existing old meskas feed the irrigated lands in the study areawith water from the delivery canals. It was decided to implement electric pumping stations asthey are advantageous over the diesel ones from many perspectives. Technically electricmotors provide a wider range of power selection (from 1 to 5 HP). They are readily availableon-the-shelf, have higher efficiency than diesel motors, require less maintenance and providegreater ease so as flexibility of operation. Economically the annual total cost per feddan ofthe electric pumping stations is 20% lower due to their lower running costs, although theestimated total capital cost of the electric pumping stations is 11% higher than the estimatedcost of the diesel pumps for the study area.The intake of Meet Yazid canal is located at Km 21 on the left-hand side of BahrShebein carrier. Canal flows with a gentle slope in north-western direction until it ends closeto Borolls coastal lake with 63 Km length. It serves a total command area of about 197000feddan through 19 branch canals. Several cross regulators are located on the canal in order tocontrol water.
  • 5. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME4984. OUTLINING THE PUMPING SYSTEM WITHIN THE STUDY AREADirect pumping system is applied at three pumping stations.• The first one is pumping station number (4) located at Km 52.67 on the left-hand sideof Meet Yazid Canal. It serves a total command area of about 35.83 feddan. Thepipeline material is composed of PVC with diameter of 200 mm and 329 m length.The pipeline has four outlets at intervals along its length which serves quaternaryunits (Marwas). Each outlet has a butterfly valve allowing water to be discharged intoopen channel. The pumping station consists of two small single stage end suctioncentrifugal pump, flow rate 40 L/s and 20 L/s, head (4.5-6 m), rated horse power (7.5-4 hp) at 1450 revaluation per min (rpm).• The second one is pumping station number (7) located at Km 55.25 on the left-handside of Meet Yazid canal. It serves a total command area of about 45.9 feddan. Thepipeline material is composed of PVC pipe with diameter of 200 mm and 253 mlength, the pipeline has five outlets at intervals along its length. The pumping stationconsists of two small single stage end suction centrifugal pump, flow rate 40 L/s and20 L/s, head (4.5-6 m), rated horse power (7.5-4 hp) at 1450 rpm.• The third one is pumping station number (12) located at Km 56.93 on the left-handside of Meet Yazid canal. It serves a total command area of about 30.00 feddan. Thepipeline material is composed of PVC pipe with diameter of 200 mm and 409 mlength, the pipeline has five outlets. The pumping station consists of two small singlestage end suction centrifugal pump. The flow rate is 30 L/s and 20 L/s. The head is (6-7.1 m) with a rated horse power of (5.5 hp) at 1450 rpm. Electric pumping stationsystem can be modified by replacing the head tank by air valve and using the directpumping method. This change in the design of the improved meska is an attempt toreduce the cost, which will be recovered from the farmers. Figure (3) shows themodified pumping station with air valve installation.Figure (3) Modified pumping station with air valve installation
  • 6. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME4995. DESCRIBING THE HYDRAULIC TRANSIENTTransient flow is the most important item in the field of pipeline design and operation.Transient flow exists in any pipeline system when the rate of flow changes abruptly for variousreasons. Some of the most common reasons are quick closing of valves accidental or planned,starting or stopping of pumps and power failure. Power failure is considered the worst-casescenario to produce hydraulic transient [11].When transient flow occurs at the pipeline system, high intensity pressure waves travelthrough the piping system until it reaches a point of some relief such as a large diameter reservoiror piping main. The shock waves will then surge back and forth between the point of relief andthe point of impact until the destructive energy is dissipated in the piping system. If severenegative pressures are allowed to occur along the pipeline, problems may arise due to pipe sealjoint failure. The maximum allowable negative pressure in the pipes is specified to be –3 m ofwater. This is considered as the limiting value for the present transient analysis. The allowablemaximum pressure along the pipeline is considered to be 4 bars. The transient flow direct impactscan be presented as follow, [12]:• The pressure fluctuation leads to high stresses. The effective value depends upon thepressure value and the rate of the pressure change. It might lead to rapture for pipes,fittings, leaking and weakened connections, damage for water meters and gauges, pipesupport damage, valves, connections, column separation and high pressure after the twocolumns rejoining which might lead to serious damage.• Vibration and its effect on the pipe structure. High levels of vibration might cause aresonance or failure or a form of fatigue failure or fatigue accumulation.• Noise and impulsive noise might induce impacts on labors.6. EXECUTING SIMULATIONSNumerical computations are carried out by using KY Pipe 2010, Ver.5 [13] code. KYPipe is a water dynamic simulation tool used to calculate pressure transients in piping systemscaused by water hammer and that leads to design and operate systems with great reliability andsafety by avoiding the potentially catastrophic effects of water hammer and other undesirablesystem transients.6.a. PIPE 2010Pipe 2010 is a powerful graphical user interface for laying out comprehensive pipesystem models, accessing and running associated engineering analysis engines and presentingresults in various ways. The models are entirely made up of pipe links end nodes and internalnodes. Using this approach only a few simple steps are required to develop and modify pipesystems and define the associated data. Friction losses through force mains shall be calculatedusing the Hazen-Williams equation:87.4852.1852.1675.10DQCLhf = (1)Where:hf is the head loss due to friction in m of waterL is the pipe length in mQ is the flow rate in m3/sD is the pipe diameter in mC is the friction coefficient which depends on roughness. For PVC material, it is common to useC=120~130.
  • 7. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME5006.b. BOUNDARY CONDITIONSTo get an accurate simulation, the mass flow rate, manometric head, pipeline profileof each meska are obtained. The simulation time of 120 second is presented. The pumpingstation is running in steady state condition and after 3 second the pumping station are stoppedand the unsteady state analysis are taken. Table (1) shows the boundary conditions for threecases.Table (1): Boundary conditions for three casesMeskaNumberofpumpsQ(L/s)Head(m)Pipelinediameter(mm)Pipelinelength(m)No. ofvalvesPipelinematerialWavespeed(m/s)No.4 2 60 6.75 200 329 3 PVC 550No.7 2 60 6.75 200 253 5 PVC 550No.12 2 50 6.75 200 405 4 PVC 5506.c. NUMERICAL RESULTSA hydraulic transient analysis was carried out on the three pumping stations to ensurethe system sufficient protection from hydraulic transient. The maximum and minimumpressures, at any point along the pipeline profile, are taken. Also the pressure history at thebeginning of meska pumping station is given.6.c.1. MAXIMUM AND MINIMUM PRESSURE ON PIPELINEThe maximum and minimum pressures inside pipeline for all tested meska areextracted at different sections in pipeline length. These distributions of pressure with time areobtained at operating conditions of meska pumping stations using numerical modeling.Figures (4), (5) and 6) show the maximum and minimum pressure during power failure whenusing air valve at the beginning of for all tested meskas. It is clear from these figures that thevalues of maximum and minimum pressure variation at any point along the pipeline profileare in the save mode. It means that the pressure variation decreases and the pipeline doesn’texpose to high stresses due to pressure change.
  • 8. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME501Figure (4) Envelops of maximum and minimum pressure formeska pumping station no.4Figure (5) Envelops of maximum and minimum pressure formeska pumping station no.7Maximum pressureHGLPipelineLower limitMinimum pressureAir valvePumping stationLower limitMinimum pressurePipelinePumping stationAir valveMaximum pressureHGLTime (sec)Elevation(meters)Time (sec)Elevation(meters)
  • 9. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME502Figure (6) Envelops of maximum and minimum pressure for meska pumping station no.12Figures (7) and (8) show the pressure variation inside the pipeline of meska pumpingstation no.7 and 12, respectively. From these figures it can be illustrated that, when shutdownpumping stations the pressure at the beginning of meska pipeline decreases from the steadystate operating pressure about 8 meter of water, reach to the negative values then the pressurerecovery reach the positive values and fluctuate about 1 meter and 0.5 meter of water for twomeasks, respectively. This means that the pipeline operate without any risks and more safety.Figure (7) Pressure history at the beginning of meska pumping station no.7PipelineMinimum pressureLower limitHGLMaximum pressurePumping stationAir valveTime (sec)Elevation(meters)Time (sec)Head(meters)
  • 10. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME503Figure (8) Pressure history at the beginning of meska pumping station no.127. EXECUTING FIELD MEASUREMENTSAfter complete studies of modified system numerically by using KY pipe code, fieldwork was conducted on the three pumping stations at Meet Yazid canal Kafr El-SheikhGovernorate.A transit-time ultrasonic flow-meter type (1010) was used to measure the volumeflow rate through the pipeline. A calibrated pressure transducer was used to measure pressureat the delivery side of the pumping units. Record card and signal conditioner, (Type ATMIO- 16E - 2) was used to collect the measured pressure value. The time history for pressuremeasurements were converted to a data file by using an application of LABVIEW software asa data acquisition system. Through another application of the MATLAB software programfor signal, the electrical output signals data file was transformed and converted to a pressurehead then pressure graph was prepared to give a complete view about the pressure history atthe measuring point. Energy analyzer, (MICRO VIP MK12) was used to measure voltage,ampere, active power, energy, apparent power, frequency and power factor. The pressurehead developed by the pumps are recorded with time at different operating conditions.8. ANALYZING AND PRESENTING THE RESULTSResults were obtained, analyzed and presented, as follows.8.a. HYDRAULIC PERFORMANCEActual measurement of flow rate is a simple way to find out how a pumping unit isperforming. Measuring flow rate and operating pressures is required to determine if apumping station is operating efficiently to convey desired flow rate. This is a cheap and easytask which should be performed regularly as part of the routine maintenance. Also, the powerabsorbed to drive the pump is a direct function of the discharge rate, the total pumping headTime (sec)Head(meters)
  • 11. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME504and the efficiency of the pump at that operating point. The efficiency of the pumping unitduring normal operation becomes a significant factor in the capital and operating costs of thepumping unit. To evaluate the performance of Mesqa pumping station, delivery pressure,(Pd), suction pressure, (Ps), discharge, (Q), static head, (Zd-Zs) and electric power consumed,(kW) were measured for three pumping stations. The total head and efficiency can becalculated as follows:)(222sdsdsdt ZZgVVgPPH −+−+⋅−=ρ(2)CHQgPW t....ρ= (3)100*..(%)PEPWOverall =η (4)Where,Ht : is the total head (m)Zd-Zs : is the potential energygPP sd⋅−ρ: is the pressure energygVV sd222−: is the kinetic energyρ : is the water density (kg/m3)W.P : is the water power (kW)E.P ; is the electric power consumed (kW)ηoverall : is the overall efficiencyTable (2) shows the test results for three pumping station. The desired total flow rate ofpumping station can be achieved from two units in operation and at least two valves areopened at the same time. Pump performance can be affected by a combination of manyfactors like sump condition and suction side.Table (2) shows that the pump delivers the design flow rate at manometric head about 10 mof water. The average overall efficiency of pumping unit (motor, coupling and pump) is about66.5%. The overall efficiency of pumping unit is about the design values according to ISO9906. Which recommended the tolerance of efficiency is (-5%). Also the pumps are operatedsatisfactory to give flow requirements MERI [14].Table (2) Hydraulic test results for three pumping stationPumpStationno.Q(l/s)Total Head(m)Electric Power(kW)Water Power(kW)OverallEfficiency(%)4 40 10.05 5.83 3.94 67.607 40 9.97 5.7 3.91 68.5912 30 9.95 4.66 2.93 62.80
  • 12. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME5058.b. TRANSIENT ANALYSIS OF PUMPING STATION NUMBER 4The pipeline is connected to air valve at the beginning of manifold to protect theinstallations against water hammer and pressure surges, while check valves are provided foreach pump to eliminate reverse flow, figure (3). A transient hydraulic analysis was carriedout on the three chosen pumping station. The pressure history was recorded with highresponse pressure transducer located at beginning of the manifold of pipeline. Figure (9)shows the pressure history during shutdown of pumping station no.4 when opening valvesno.2 and 3 also the measured flow rate of two pumps are 60 l/s. It can be seen that thepressure at the pipeline decrease gradually to reach (-2 m) water and increase to (1.2 m) waterwhen using air valve.Figure (9) pressure history during power failureusing air valve when open valves no. 2 and 3Figure (10) pressure history during powerfailure without air valve when open valvesno. 2 and 3Figure (10) shows the pressure history during shutdown of pumping station no.4 whenopening valves no.2 and 3. Also the measured flow rates, of two pumps, are 61.2 l/s. It can beseen that the pressure at the pipeline decreases gradually to reach (-2.4 m) water and increaseto about (-1.5 m) water without air valve. From figures (9) and (10), it can be concluded thatthe pressure decreases at shutdown the pumps in case of without air valve more than in caseof using air valve. Also the negative pressure fluctuated inside the pipeline in case of notusing air valve. Figure (11) shows the pressure history during shutdown the pumping stationand the last two valves no.3 and no.4 are opened with air valve installation. The measuredflow rate of two pumps are 62 l/s. Figure (12) illustrates the pressure history during shutdownthe pumping station and the two last valves no.3 and 4 are open without air valveinstallation. The measured flow rate of two pumps is 60 l/s.
  • 13. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME506Figure (11) pressure history during powerfailure using air valve when open valves no. 3and 4Figure (12) pressure history during powerfailure without air valve when open valves no.3 and 4It is clear from figures (11) and (12) that when using air valve the pressure history fluctuatedinside pipe line are about the positive values that means the installation of air valve at thebeginning of the pipeline decrease the causing of negative pressures.8.c. TRANSIENT ANALYSIS OF PUMPING STATION NUMBER 7Pumping station number 7 consists of two pump sets connected in parallel with eachother, the discharge of one pump is 40 l/s and the other one is 20 l/s the total capacity of thepumping station are 60 l/s at the static head (6-7.1) m of water the variation of static headaccording to the Meet Yazid canal water level.Figure (13) illustrates the pressure history during shutdown of pumping stationnumber 7 when opening valve no.5 also the measured flow rate of two pumps are 52 l/s. Itcan be seen that the pressure at the pipeline decrease suddenly to reach (-0.85 m) water andincrease to fluctuated about (0.85 m) water when using air valve.Figure (14) shows the pressure history during startup and shutdown the pumpingstation number 7 when opening the valve number 5 and flow rate measured 52 l/s without airvalve installation. From this figure it can illustrate that the pressure inside the pipelineincreases suddenly when startup the pumps to reach 8 m of water and decreases gradually toreach about 6 m of water. Also when shutdown the pumps, the pressure inside the pipelinedeceases suddenly reach to (-2.1) m of water and increases to reach (2.2) m of water thenfluctuate about 0.5 m of water.
  • 14. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME507Figure (13) pressure history during power failureusing air valve when open valve no. 5Figure (14) pressure history during start upand power failure without air valve whenopen valve no. 5Figure (15) illustrates the pressure history during shutdown of pumping station no.7when opening valves no.2 and 4 also the measured flow rate of two pumps are 54 l/s, andusing air valve. From this figure it can illustrate that the pressure inside the pipeline increasessuddenly when starting up the pumps to reach 8 m of water and deceases gradually to reachabout 5.8 m of water. Also when shutdown the pumps, the pressure inside the pipelinedeceases suddenly reach to -2 m of water and increases to reach 2.1 m of water then fluctuateabout 0.2 m of water.Figure (16) shows the pressure history during starting up and shutdown the pumpingstation number 7 when opening the valves number 2 and 4. The total flow rate measured is61.5 l/s. From this figure it can illustrate that, the pressure inside the pipeline increasessuddenly when starting up the pumps to reach 7.8 m of water and deceases gradually to reachabout 4.7 m of water, also when shutdown the pumps the pressure inside the pipelinedeceases suddenly reach to (-2.9) m of water and increases to reach (1.35) m of water thenfluctuate about this value.Figure (15) pressure history during powerfailure using air valve when open valves no. 2and 4Figure (16) pressure history during start upand power failure without air valve whenopen valves no. 2 and 4
  • 15. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME508When shutdown the pumping station at the design flow rate without air valve installation,figure (16). The negative pressure values reach to (-3) m of water. Figure (15) shows that thenegative pressure values reach -2 m of water with air valve installation. It can be concludedthat using air valve at the beginning of meska pipeline allows the pipeline operating conditionto be more safe.8.d. TRANSIENT ANALYSIS OF PUMPING STATION NUMBER 12Pumping station number 12 consists of two pump sets connected in parallel with eachother. The discharge of one pump is 30 l/s and the other one is 20 l/s. The total capacity ofthe pumping station is 50 l/s at the static head 6 to 7.1 m of water, and five alfalfa valvesdistributed along the pipeline to irrigate all served area.Figure (17) illustrates the pressure history during starting up and shutdown thepumping station number 12 when valve number 5 is opening alone and measured flow rate is40 l/s with air valve installation. From this figure it can illustrate that the pressure inside thepipeline increases suddenly when starting up the pumps to reach (6.8) m of water anddeceases gradually to reach about (5) m of water. Also when the pumps were shut down thepressure inside the pipeline deceased suddenly to reach -2 m of water and increased to reach2.7 m of water then fluctuate about (1) m of water.Figure (18) shows the pressure history during starting up and shutdown the pumpingstation number 12 when valve number 5 is opening alone and measured flow rate is flow rate40 l/s without air valve installation. From this figure it can illustrate that the pressure insidethe pipeline increases suddenly when the pumps were upstarted to reach (8) m of water anddeceased gradually to reach about 6.8 m of water.Also when the pumps were shut down the pressure inside the pipeline deceased suddenlyreach to -3.1 m of water and increased to reach (2.1) m of water then fluctuate about zero mof water.Figure (17) pressure history during start up andpower failure using air valve when open valveno. 5Figure (18) pressure history during start upand power failure without air valve whenopen valve no. 5From the two figures it can be seen that the negative pressure inside the pipeline without airvalve installation while, in the case of using air valve pipeline exposes to positive value.The advantages of air valves are easy operation, low maintenance, low operation cost andhigh reliability. Direct pumping systems save the cost of head tank construction and
  • 16. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME509maintenance, furthermore the stand pipe intervals at the end of each valve are play theimportant role to prevent the system from water hammer phenomena. This intervals aredamping the pressure waves when shutdown the system.9. COMPARING FIELD AND NUMERICAL RESULTSFigure (19.a) and (19.b) show a sample of the executed comparison between the fieldand numerical results of pressure variation inside the pipeline meska no.4.From the figure, it is clear that the numerical curve complies well the field curve.Generally, the matching between them is fairly good and the pressure details inside the pumpare obtained by using the software without carrying the filed measurements. The smalldeviation is attributed to the smoothness of the fittings and the use of friction coefficient "C"for PVC material. In the present study a value of C is equal to 120.Figure (19.a) Numerical results Figure (19.b) Field resultsFigure (19) Comparison between the numerical and field results for meska no.410. UNDERGOING A FINANCIAL AND AN ECONOMIC ANALYSESFinancial and economic analyses were conducted in order to improve meskas in thestudy area and to compare the cost of air valve versus delivery tank based on 2009 prices.The comparison was based on the total cost per feddan. The main items affect thetotal cost of improving meska are backfilling, pipeline, pump house, pumps and others suchas valves, head tank ( as in IIP1), air valves ( as in IIP2 or IIIMP) etc. The average cost forimproving meska in IIP1 is about 8500 LE/fed. The average cost for improving meska in IIP2is about 6000 LE/fed. The cost of pipe line was about 30% from the total cost. Thecontribution of direct pumping in the cost saving is decreasing pipe line diameter from (315:500 mm) to (200: 400 mm) and replacing head tank by air valve which cost about 18000 LEfor meska (served about 50 feddan), while, air valve cost is equal to 200 LE. The decreasingof pipe line diameter leads to increase pumping operation duration from 16 to 20 hr/day,according to new design criteria of IIP2 and IIIMP projects, increase flow velocity anddecreasing of water duty from 1.45 to 1.05 l/s/fed. Cost saving from decreasing pipe linediameter is equal to 250 LE/fed. So, the total cost saving is about 606 LE/feddan.
  • 17. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME51011. CONCLUSION AND RECOMMENDATIONBased on the results reached in the present research, the following was concluded:• The direct pumping systems save about 606 LE/fadden due to replace the headtank by air valve.• Pipeline system equipped with air valve, air vent and distribution valves iseffective and is a safe solution for water hammer control.• KY Pipe 2010 code is a hand tool for design. It can predict accurately thedifferent pressure phenomena and assist the choice of suitable protectiondevices to protect the water hammer phenomena and to evaluate system.• Comparison between the computation and field measurements indicated that thenumerical simulation results were found to comply well with actual valuesobtained from the field measurements.At the design stage, it is recommended to:• Check the transient state especially for long pipelines (more than 500 m). It maybe required more than one air valve.• Slow the time of opening and closing selected distribution valves not less than 4second.12. REFERENCES[1] Dalal Alnagar Director (RCTWS), Ministry of Water Resources and Irrigation, "Policiesand strategic options for water management in the Islamic countries", Internationalhydrological program Tehran, Islamic Republic of Iran, 15-16 Dec. 2003.[2] R.J.Oosterbaan, International Institute for Land Reclamation and Improvement (ILRI),Wageningen, "Impacts of the Irrigation Improvement Projects in Egypt", Consultancy Reportto the Egyptian-Dutch Advisory Panel on Land Drainage and Drainage Related WaterManagement, 2010.[3] Walid E. Elshorbagy, "Impact Assessment of an Irrigation Improvement Project inEgypt", Water Resources Management, 2000.[4] New Partnership for Africa’s Development (NEPAD), "Support to NEPAD–CAADPImplementation “, Bankable Investment Project Profile, 2005.[5] M. Allam, F. El-Gamal, and M. Hesham, "Irrigation Systems Performance in Egypt",Irrigation Systems Performance. Options méditerranéennes, Series B, no 52, 2004.[6] M.N. Allam Department of Irrigation and Drainage Engineering, Faculty of Engineering,Cairo University, "Participatory Irrigation Water Management in Egypt: Review andAnalysis", Options méditerranéennes Series B, no 48, 2009.[7] World Bank, "Implementation Completion and Results Report: Irrigation ImprovementProject ", Report, 2007.[8] Sabour Consultant, "Terms of Reference for the Tendering of Consulting Services for theIntegrated Irrigation Improvement and Management Project (IIIMP) and Instruction toTenders", Report, 2008.[9] Hany G. Radwan, Ashraf S. Zahloul and Kamal A. Ibrahim, "Analysis of OptimalVelocity for Improved Irrigation Design in Egypt", Canadian Journal on Environmental,Construction and Civil Engineering Vol.2 No. 5,2011, pp.94-102.
  • 18. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME511[10] K. Al-Askari, G. Fawzy and M.A.Younes, "Electrification of Meska Pumping Stationsas an Option for Future Irrigation Improvement Projects in Egypt", Third Arab waterRegional Conference National Water Research Center, 9-11 Dec. 2005.[11] Kroon, R., "Water Hammer: Causes and Effects", AWWA Journal, 1984, pp. 39-45.[12] Lingireddy, "Pressure Surges in Pipeline Systems Resulting From Air Releases",AWWA Journal, 2004, pp. 88-94.[13] Don J. Wood and Lingireddy, "KY Pipe 2010 documentation Version 5" AdvancedScientific Computing, Ltd, Lexington, USA 2010.[14] Mechanical & Electrical Research Institute (MERI), "Direct Pumping hydraulic test forIrrigation Improvement project at Meet Yazid canal", Technical report, Delta Barrage, Egypt,2008.[15] Omar K M Ouda, Abdullatif A. Al-Shuhail, Tawfiq Qubbaj and Rana Samara,“Assessing the Applicability of Ground Penetrating Radar (GPR) Techniques for EstimatingSoil Water Content and Irrigation Requirements in the Eastern Province of Saudi Arabia: AProject Methodology”, International Journal of Advanced Research in Engineering &Technology (IJARET), Volume 4, Issue 1, 2013, pp. 114 - 123, ISSN Print: 0976-6480,ISSN Online: 0976-6499.[16] Anubhav Gupta and Harish Bansal, “Design of Area Optimized AES Encryption Coreusing Pipelining Technology”, International Journal of Electronics and CommunicationEngineering &Technology (IJECET), Volume 4, Issue 2, 2013, pp. 308 - 314, ISSN Print:0976- 6464, ISSN Online: 0976 –6472.