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Effect of Geometrical Parameters in Coefficient of Discharge and Reynolds Number Through Venturimeter

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Effect of Geometrical Parameters in Coefficient of Discharge and Reynolds Number Through Venturimeter International Journal of Innovative Technology and Exploring Engineering (IJITEE) ISSN: 2278-3075, Volume-8 Issue-12, October 2019 Effect of Geometrical Parameters in Coefficient of Discharge and Reynolds Number through Venturimeter G V Chaitanya, A Shivam Singh, R Gautham, A Pavan Kumar Reddy, N Balaji ABSTRACT: The experiment is intended to find the Venturimeter consists of three part, which are converging, performance characteristics of venturimeter with different beta throat and gradual diverging part. The cross sectional area of ratios (β) 0.6705, 0.67 and 0.56. The type of flow in the pipe and the converging part of venturimeter decreases as that of inlet discharge, represent on Reynolds number (Re) and coefficient of pipe, throat section of the venturimeter has small uniform discharge (Cd) through the pipe flow. Standard fluid (water) is cross sectional area and divergent part is the gradual taken as working fluid having density (ρ) 1000 kg/m3 and manometric fluid as mercury, having density (ρ) 136000 kg/m3. increase of cross sectional area of the venturimeter. The Kinematic viscosity depends on density and dynamic viscosity. pressure difference between the inlet and throat is given by The Dynamic viscosity (µ) of water is 0.0006532 and 0.000798 the Bernoulli‟s equation which states that “In a steady ideal Ns/m2 taken in two different temperature as 30̊ C and 40̊ C. flow an incompressible fluid, the total energy at any point is Upstream length 1.28m, 1.38m and 1.48m are taken in constant”. The total energy consists of pressure energy, experiment and found that the Reynolds number of the working kinetic energy and potential energy. fluid increases with increase in coefficient of discharge and 푝 푣2 푝 푣2 1 + 1 + 푧 = 2 + 2 + 푧 initially increases and certainly decreases with increase in 휌푔 2푔 1 휌푔 2푔 2 upstream length. But above equation is for ideal fluid and assumed that the KEYWORDS: Venturimeter, Beta ratios (β), coefficient of flow is steady, non-viscous and irrotational. For real fluids discharge (Cd),Upstream length, Reynold’s number (Re). there will be some pressure losses due to friction and roughness of the pipe, hence major losses due to friction is I. INTRODUCTIONS also taken in account to measure the pressure head theoretically. The actual pressure heads is measured with the Flow meter are being commonly used in many industries to help of pressure difference between the pipe and throat of measure the volumetric flow through the pipe. These flow the venturimeter which is recorded by differential meter are usually differential pressure type. Venturimeter is manometer. an obstruction type flow meter device named after Giovanni Battista Venture (1746- 1822) an Italian physicist who introduced Venturi Effect in the fluid flowing through the pipe. Venturi Effect is the reduction of fluid pressure in throat diameter and increase the velocity. Clemens Herschel (1842-1930), an American hydraulic engineer developed an accurate venturimeter which was a first large scale device used to measure the flow rate and widely used in many industries thereafter. venturimeter works based on the principle of Bernoulli‟s, when cross sectional area of the flow is reduced then a pressure difference is created between the different areas of flow and due to which the velocity of fluid increases and then decreases which helps in measuring the difference in pressure. Fig: 2 Schematic representation of experimental setup The manometer has two pipe in which one is connected to inlet having same diameter as that of pipe and other to the Revised Manuscript Received on October 05, 2019. throat of the venturimeter. The fluid velocity increases as G V Chaitanya, Department of Mechanical Engineering Vel Tech Rangarajan Dr Sagunthala R&D Institute of Science and Technology, passes through convergent section and gradually decreases Avadi, Chennai. through the divergent cone. The main advantage of using A Shivam Singh, Department of Mechanical Engineering Vel Tech venturimeter in the experiment is high accuracy of Rangarajan Dr Sagunthala R&D Institute of Science and Technology, coefficient of discharge. Compared to orifice it has quick Avadi, Chennai. R Gautham, Department of Mechanical Engineering Vel Tech pressure recovery. Rangarajan Dr Sagunthala R&D Institute of Science and Technology, Avadi, Chennai. A Pavan Kumar Reddy, Department of Mechanical Engineering Vel Tech Rangarajan Dr Sagunthala R&D Institute of Science and Technology, Avadi, Chennai. N Balaji Department of Mechanical Engineering Vel Tech Rangarajan Dr Sagunthala R&D Institute of Science and Technology, Avadi, Chennai. Published By: Retrieval Number: L35481081219/2019©BEIESP Blue Eyes Intelligence Engineering DOI: 10.35940/ijitee.L3548.1081219 4897 & Sciences Publication Effect of Geometrical Parameters in Coefficient of Discharge and Reynolds Number through Venturimeter II. EXPERIMENTAL SETUP AND SPECIFICATION Inlet pipe 1 0.025 4.9087 Three pipes (galvanized iron) of different diameter (20 mm, Throat 1 0.01675 2.2035 25 mm, 30 mm) and different upstream length (1.28m, Inlet pipe 2 0.020 3.141 1.38m 1.48used respectively are used in the experiment. All Throat 2 0.01341 1.4124 the pipes are connected with single pipe with „T‟ joint at one The pump is switched and the valve of one pipe is initially end and at other with venturimeter having convergent cone opened full and then gradually closed to require the diameter as same as that of inlet pipe and throat diameter appropriate manometric heads. Manometric heads are noted (13.47 mm, 16.75 mm, 16.75 mm) respectively. The in the tabulation and then actual discharge is found by mercury differential U tube manometer is used where its one closing the collecting tank and time is noted for the 5 cm limb is connected to all the inlet section of different pipe and rise of water by observing the rise of water level in fixed another limb is connected to the throat section of different piezometer. The below formula is used to find the actual venturimeter. discharge (푄푎푐푡) of water through the pipe. 퐴푕 푄 = 푚3/푠 푎푐푡 푡 Table: 2 parametric values of pipe s. Time 푄 Time 푄푎푐푡 no in s(for 푎푐푡 in s(for (pipe 25 mm) (pipe 20 mm) −4 20 mm −4 25 mm 푖푛 푋10 푚3 푖푛 푋10 푚3 pipe) pipe) /푠 /푠 1 61 1.967 37.06 3.237 2 35 3.428 21 5.714 3 28 4.285 16.5 7.272 4 20 6 13.2 9.090 5 17 7.058 11.2 10.71 6 16 7.5 10.4 11.534 7 14.5 8.275 9.4 13.18 Fig: 1 Schematic Representation of Venturimeter with Manometer 8 14 8.571 9 13.289 Centrifugal pump is used to drive the water from tank to the 9 11.4 10.52 8.1 14.814 pipes which has following specification (2 phase, 240V, 10 9.6 12.5 7.7 15.605 50Hz, kW/HP: 0.37/0.5, Speed: 2800, Eff: 22%). Gate Pressure head (H) is calculated by the difference of heads of valves (cast iron) are used to control the flow of water two limbs in manometer as shown below and then flowing through the pipe. The outlet of all the pipe are theoretical discharge (푄 ) is found by the following formula connected to single pipe and the water is collected in a surge 푡푕 푆 푚푒푟푐푢푟푦 −2 tank of (40mm x 60mm) dimensions respectively. The surge 퐻 = 푕1 − 푕2 − 1 푋 10 푚 tank is fitted with piezometer which measures the level of 푆푤푎푡푒푟 푃 − 푃 water collected inside the surge tank when the gate valve of 푕 = 1 2 = 퐻 푚푒푡푒푟 푓 bend pipe is closed. 휌푔 푎 푋푎 2푔퐻 1 2 3 푄푡푕 = 푚 /푠 2 2 푎1 − 푎2 The ratio of actual discharge (푄푎푐푡) and theoretical discharge (푄푡푕)is coefficient of discharge and then tabulated as shown 푄푎푐푡 푐푑 = 푄푡푕 Table: 3 parametric values of pipe of diameter 20mm 푕1 푕2 H 푄푎푐푡 푄푡푕 퐶푑 (cm) (cm) (m) X10-4(푚3/푠) X10-4(푚3/푠) 25.1 21 0.517 1.967 5.034 0.391 Fig: 3 Experimental setup of Venturimeter 26.2 19.9 0.794 3.428 6.240 0.549 27.4 18.7 1.096 4.285 7.332 0.584 III. PROCEDURE 28.8 17.4 1.436 6 8.394 0.715 The experiment is started with removing the air from the 30.2 15.9 1.802 7.058 9.401 0.750 pipe and ensured that the manometricpipe are connected 31.4 14.6 2.117 7.5 10.19 0.736 tightly to the pipe inlet diameter and center in throat 32.7 13.4 2.432 8.275 10.921 0.758 diameter of the pipe. The area of the pipe and throat of 35.1 10.8 3.062 8.571 12.255 0.699 different pipe is calculated using the following formula. 38.1 7.8 3.818 10.52 13.685 0.770 휋푑2 푎 = 푚2 43.7 3.4 5.204 12.5 15.977 0.782 4 Table: 1 Area of throat and inlet Area in 푚2 in Pipe/Throat Diameter in m x10-4 Published By: Retrieval Number: L35481081219/2019©BEIESP Blue Eyes Intelligence Engineering DOI: 10.35940/ijitee.L3548.1081219 4898 & Sciences Publication International Journal of Innovative Technology and Exploring Engineering (IJITEE) ISSN: 2278-3075, Volume-8 Issue-12, October 2019 Table: 4 parametric values of pipe of diameter 25mm (beta ratio) are experimentally investigated and calibrated in graph. 푕1 푕2 H 푄푎푐푡 푄푡푕 퐶푑 (cm) (cm) (m) X10-4푚3/푠 X10-4푚3/푠 25 21.6 0.428 3.237 7.149 0.453 27 20.2 0.857 5.714 10.11 0.565 28.7 18.4 1.298 7.272 12.444 0.584 30.8 16.4 1.814 9.090 14.713 0.618 32.8 14.3 2.331 10.71 16.677 0.642 34.9 12.3 2.848 11.534 18.432 0.6255 36.6 10.5 3.289 13.18 19.808 0.665 38.5 8.5 3.78 13.289 21.237 0.6257 40.3 7.4 4.145 14.814 22.239 0.667 43.9 3.9 5.04 15.605 24.522 0.636 Thevalue of friction factor (푓), actual velocity 푉푎 is found by following equation.
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