{ "metadata": { "name": "", "signature": "sha256:c4763e5901f11f7dc8699953a49ca33923db1ee352fad2402763eb19eb84fa47" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 06:Momentum Analysis of Flow Systems" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6-1, Page No:248" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import scipy.integrate\n", "\n", "#Variable Decleration\n", "a=1 #Lower limit of the intergral to be carried out\n", "b=0 #Upper limit of the intergral to be carried out\n", "\n", "#Intergration\n", "\n", "func = lambda y:-4*y**2 #Decleration of the variable and the function to be integrated\n", "X=scipy.integrate.quadrature(func, a,b)\n", "\n", "#Result\n", "\n", "print \"The Momentum Flux correction factor becomes\",round(X[0],2)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The Momentum Flux correction factor becomes 1.33\n" ] } ], "prompt_number": 21 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6-2, Page No:251" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable Decleration\n", "m_dot=14 #Mass flow rate in kg/s\n", "rho=1000 #Density of water in kg/m^3\n", "theta=pi/6 #Angle at which the pipe is deflected w.r.t the horizontal\n", "A1=0.0113 #Cross-sectional Area at the inlet of the elbow in m^2\n", "A2=7*10**-4 #Cross-sectional Area at the outlet of the elbow in m^2\n", "C=10**-3 #Conversion factor\n", "g=9.81 #Acceleration due to gravity in m/s^2\n", "z2=0.3 #Elevational difference betweem inlet and outlet in m\n", "z1=0 #Considering Datum in m\n", "beta=1.03 #Momentum correction factor \n", "\n", "#Calculations\n", "V1=m_dot/(rho*A1) #Velocity at the inlet of the elbow in m/s\n", "V2=m_dot/(rho*A2) #Velocity at the outlet of the elbow in m/s\n", "\n", "#Part(a)\n", "#Applying the Bernoulli Principle\n", "#Simplfying the calculations in two steps\n", "a=(V2**2-V1**2)/(2*g)\n", "P1_gauge=(a+z2-z1)*g*rho*C #Gauge pressure at inlet in kPa\n", "\n", "#Part(b)\n", "#Applying the momentum equation\n", "#Anchoring forces required\n", "F_rx=-(P1_gauge*1000*A1)+(beta*m_dot*((V2*cos(theta))-V1)) #N\n", "F_rz=beta*m_dot*V2*sin(theta) #N\n", "\n", "#Result\n", "print \"The gauge pressure at the inlet is\",round(P1_gauge,1),\"kPa\"\n", "print \"The anchoring forces required to hold it in place are\",round(F_rx,),\"N and\",round(F_rz),\"N\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The gauge pressure at the inlet is 202.2 kPa\n", "The anchoring forces required to hold it in place are -2053.0 N and 144.0 N\n" ] } ], "prompt_number": 51 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6-3, Page No:253" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable decleration\n", "beta=1.03 #Momentum Correction factor\n", "m_dot=14 #mass flow rate in kg/s\n", "V2=20 #Velocity at outlet in m/s\n", "V1=1.24 #Velocity at inlet in m/s\n", "P1_gauge=202200 #gauge pressure at inlet in N/m^2\n", "A1=0.0113 #Area at the inlet in m^2\n", "\n", "#Calculations\n", "#Applying the momentum equation\n", "F_rx=-beta*m_dot*(V2+V1)-P1_gauge*A1 #Horiznotal force in N\n", "\n", "#Result\n", "print \"The horizontal force is\",round(F_rx),\"N\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The horizontal force is -2591.0 N\n" ] } ], "prompt_number": 52 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6-4, Page No:253" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable Decleration\n", "beta=1 #Momentum correction factor\n", "m_dot=10 #Mass flow rate in kg/s\n", "V1=20 #Velocity of flow of water in m/s\n", "\n", "#Calculations\n", "#Applying the momentum equation\n", "F_r=beta*m_dot*V1 #The force exerted in N\n", "\n", "#Result\n", "print \"The force exerted is\",round(F_r),\"N\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The force exerted is 200.0 N\n" ] } ], "prompt_number": 53 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6-5, Page No:254" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable decleration\n", "W_s=11 #Wind speed in km/h\n", "C=3.6**-1 #Conversion from km/h to m/s\n", "D=9 #Diameter of the blade in m\n", "rho1=1.22 #Density of air in kg/m^3\n", "W_actual=0.4 #Actual power generated in kW\n", "\n", "#Calculations\n", "#Part(a)\n", "V1=W_s*C #Velocity in m/s\n", "m_dot=(rho*V1*pi*D**2)/4 #Mass flow rate of air in kg/s\n", "W_dot_max=0.5*m_dot*V1**2*10**-3 #Work done in kW\n", "n_windturbine=W_actual/W_dot_max #Efficiency of the turbine-generator \n", "\n", "#Part(b)\n", "V2=V1*((1-n_windturbine)**0.5) #Exit velocity in m/s\n", "\n", "#Applying momentun equation\n", "F_r=m_dot*(V2-V1) #Force exerted in N\n", "\n", "#Result\n", "print \"The efficiency of the turbine is\",round(n_windturbine,3)\n", "print \"The horizontal force exerted is\",round(F_r,1),\"N\"\n", "#Answer differs by 0.5 due to floating point accuracy in second part" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The efficiency of the turbine is 0.361\n", "The horizontal force exerted is -145.5 N\n" ] } ], "prompt_number": 59 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6-6, Page No:256" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable Decleration\n", "V_gas=3000 #Velocity of the gas exiting in m/s\n", "m_dot_gas=80 #mass flow rate of gas escaping in kg/s\n", "m_spacecraft=12000 #mass of the spacecraft in kg\n", "delta_t=5 #Time in s\n", "#Calculations\n", "#Part(a)\n", "a_spacecraft=-(m_dot_gas*V_gas)/m_spacecraft #Acceleration of the spacecraft in m/s^2\n", "\n", "#Part(b)\n", "dV=a_spacecraft*delta_t #Change in velocity of the spacecraft in m/s\n", "\n", "#PArt(c)\n", "F_thrust=-(m_dot_gas*V_gas)/1000 #Thrust force exerted in kN\n", "\n", "#Result\n", "print \"The acceleration of the spacecraft is\",round(a_spacecraft),\"m/s^2\"\n", "print \"The change in velocity is\",round(dV),\"m/s\"\n", "print \"The thrust force exerted is\",round(F_thrust),\"kN\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The acceleration of the spacecraft is -20.0 m/s^2\n", "The change in velocity is -100.0 m/s\n", "The thrust force exerted is -240.0 kN\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6-7, Page No:257" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable Decleration\n", "V_dot=70 #Volumertic Flow rate in L/min\n", "D=0.02 #Inner diameter of the pipe in m\n", "C=60*10**3 #Conversion factor\n", "rho=997 #Density of water in kg/m^3\n", "P1_gauge=90000 #Pressure at location in Pa\n", "X=57 #Total weight of faucet in N\n", "\n", "#Calculations\n", "V=((V_dot*4)/(pi*D**2))/C #Velocity of flow in m/s\n", "m_dot=(rho*V_dot)/C #mass flow rate in kg/s\n", "\n", "#Applying the Momentum equation\n", "F_rx=-(m_dot*V)-((P1_gauge*pi*D**2)/4) #X-component of force in N\n", "F_rz=-m_dot*V+X #z-Component of force in N\n", "\n", "#Result\n", "print \"The net force exerted on the flange in vector notation is Fr\",round(F_rx,2),\"i+\",round(F_rz,2),\"k N\"\n", "#NOTE:The answer in the textbook differs due to decimal point accuracy difference in computation" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The net force exerted on the flange in vector notation is Fr -31.99 i+ 53.29 k N\n" ] } ], "prompt_number": 12 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6-9, Page NO:266" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable Decleration\n", "rho=1000 #Denisty of water in kg/m^3\n", "D=0.10 #Diameter of the pipe in m\n", "V=3 #Average velocity of water in m/s\n", "g=9.81 #Acceleration due to gravity in m/s^2\n", "m=12 #Mass of horizontal pipe section when filled with water in kg\n", "r1=0.5 #Moment arm 1 in m\n", "r2=2 #Moment arm 2 in m\n", "\n", "#Calculation\n", "m_dot=rho*((pi*D**2)/4)*V #Mass flow rate in kg/s\n", "W=m*g #Weight in N\n", "\n", "#Applying the momentum equation\n", "M_A=r1*W-(r2*m_dot*V) #Momentum about point A in N.m\n", "\n", "#Setting M as zero and using the momentum equation\n", "L=((2*r2*m_dot*V)/W)**0.5 #Length in m\n", "\n", "#Result\n", "print \"The bending Moment at A is\",round(M_A,1),\"N.m and the length required is\",round(L,1),\"m\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The bending Moment at A is -82.5 N.m and the length required is 1.5 m\n" ] } ], "prompt_number": 14 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6-9, Page No:267" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable Decleration\n", "V_dot_nozzle=5 #Volumertic flow rate in L/s\n", "D_jet=0.01 #Diameter of the jet in m\n", "C=10**-3 #Conversion Factor\n", "n_dot=300 #R.P.M of the nozzle\n", "r=0.6 #Radial arm in m\n", "m_dot=20 #Mass flow rate in kg/s\n", "s=60**-1 #Conversion factor\n", "#Calculations\n", "V_jet_r=(V_dot_nozzle*4)/(pi*D_jet**2)*C #Velocity relative to the rotating nozzle in m/s\n", "w=(2*pi*n_dot)*s #Angular speed in rad/s\n", "V_nozzle=r*w #Tangential Velocity in m/s\n", "\n", "#Applying thr relative velocity principle\n", "V_jet=V_jet_r-V_nozzle #Velocity of the jet in m/s\n", "\n", "#Applying the momentum Equation and using the torque concept\n", "T_shaft=r*m_dot*V_jet #Torque transmitted through the shaft in N.m\n", "W_dot=w*T_shaft*C #Power generated in kW\n", "\n", "#Result\n", "print \"The sprinkler-type turbine has the potential to produce\",round(W_dot,1),\"kW\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The sprinkler-type turbine has the potential to produce 16.9 kW\n" ] } ], "prompt_number": 33 } ], "metadata": {} } ] }