{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 2: Dimensional Analysis" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.10: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_4E,page 31.\n", "\n", "disp('From phi equal to Qm/(Dm^3*Nm)=Qp/(Dp^3*Np) and psi=g*Hm/(Dm^2*Nm^2)=g*Hp/(Dp^2*Np^2), we have Qm=Qp*((Dm/Dp)^3)*(Nm/Np) and Hm=Hp*((Dm/Dp)^2)*(Nm/Np)^2)')\n", "\n", "Q_p=25\n", "//let x=Dm/Dp=1/5\n", "x=1/5\n", "N_m=3600\n", "N_p=1800\n", "H_p=160\n", "E=0.92\n", "//let y=rho*g=62.4\n", "y=62.4\n", "\n", "Q_m=Q_p*((x)^3)*(N_m/N_p)\n", "printf('\n The value of Q_m is equal to %g ft^3/s',Q_m)\n", "\n", "H_m=H_p*((x^2)*(N_m/N_p)^2)\n", "printf('\n The value of H_m is equal to %g ft',H_m)\n", "\n", "P_s=E*y*Q_m*H_m/550//1/550 is conversion factor\n", "printf('\n The value of P_s is equal to %0.02f hp',P_s)\n", "" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.11: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_4S,page 31.\n", "disp('From phi equal to Qm/(Dm^3*Nm)=Qp/(Dp^3*Np) and psi=g*Hm/(Dm^2*Nm^2)=g*Hp/(Dp^2*Np^2), we have Qm=Qp*((Dm/Dp)^3)*(Nm/Np) and Hm=Hp*((Dm/Dp)^2)*(Nm/Np)^2)')\n", "\n", "Q_p=42\n", "//let x=Dm/Dp=1/5\n", "x=1/5\n", "N_m=3600\n", "N_p=1800\n", "H_p=50\n", "E=0.92\n", "rho=998\n", "g=9.81\n", "//let y=Q/60=0.011166\n", "y=0.011166\n", "\n", "Q_m=Q_p*((x)^3)*(N_m/N_p)\n", "printf('\n The value of Q_m is equal to %g cmm',Q_m)\n", "\n", "H_m=H_p*((x^2)*(N_m/N_p)^2)\n", "printf('\n The value of H_m is equal to %g m',H_m)\n", "\n", "Q_mr=0.67//rounded off\n", "P_s=E*rho*g*(y)*H_m\n", "printf('\n The value of P_s is equal to %0.1f W',P_s)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.1: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_1,page 18.\n", "\n", "//These are examples given in the book,they are used to teach conversions from one unit to another\n", "\n", "rho=0.075//lbm/ft^3\n", "\n", "V=120\n", "\n", "RHO_c=rho/32.2//rho conerted to slug/ft^3\n", "\n", "disp('The initial value of rho was given in lb/ft^3. In order to convert it to slug/ft^3,we have used the conversion factor 1/32.2.')\n", "\n", "printf('\nThe initial value of rho was 0.075lb/ft^3 after coverting it is %0.5f slug/ft^3',RHO_c)\n", "\n", "p_d=RHO_c*V^2/2\n", "\n", "printf('\nHence the value of dynamic pressure is %0.2f (slug/ft^3)(ft/s)',p_d)\n", "\n", "p_dc=p_d/(12^2)//converting slug*s/ft^2 to lbf/in^2\n", "\n", "printf('\nThe final value of dynamic pressure is %0.3f lbf/in^2',p_dc)\n", "\n", "printf('\nHence we can say that the dynamic power is equal to %0.3f psi.',p_dc)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.2: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_2,page 18.\n", "\n", "// This numerical is used an example to teach conversion factors\n", "T0=600\n", "T1=550\n", "Cp=0.24\n", "halfVsquare=Cp*32.2*778*(T0-T1)\n", "printf('\n The value of half of V^2 is %g (Btu/slug*R)(lbf-ft/Btu)(R)',halfVsquare)\n", "printf('\n The value of half of V^2 ca also be written as %g lbf-ft/slug',halfVsquare)\n", "printf('\n The value of half of V^2 is also equal to %g (ft/s)^2',halfVsquare)\n", "V=sqrt(halfVsquare*2)\n", "printf('\n\n The value of V is equal to %0.1f ft/s',V)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.3: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_3,page 19.\n", "\n", "// This numerical is used an example to teach conversion factors\n", "\n", "rho=0.85*62.4\n", "p=50//in psi\n", "g=32.2\n", "disp('Since pressure is the product of density,gravitaional accelaration and head, we can convert pressure in psi to head in ft using suitable conversion factors.')\n", "H=p*144/( (rho/32.2)*32.2)\n", "printf('The value of head H is given by %0.1f lb/ft^2/((slug/ft^3)*(ft/s^2))',H)\n", "printf('\nThus the value of H is equal to %0.1f ft',H)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.4: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_4,page 19.\n", "\n", "//converting dynamic pressure of air from 2_1 to wg\n", "\n", "pd=16.77//lbf/ft^2\n", "rho_w=62.4/32.2\n", "g=32.2\n", "disp('From pressure=density*gravitational accelaration *head, we can find out the value of head')\n", "h=pd/(rho_w*g)\n", "printf(' Hence the value of head H is %0.3f (lbf/ft^2)/(lbf/ft^3)',h)\n", "printf('\n The value of head H can also be given by %0.3f ft',h)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.5: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_1E,page 29.\n", "Q1=80\n", "N1=1000\n", "N2=1500\n", "delta_p1=150\n", "P_s1=8\n", "\n", "disp('From phi_2=phi_1 we have Q2/(D^3*N2)=Q1/(D^3*N1)')\n", "Q2=Q1*N2/N1\n", "printf(' The value of Q2 is equal to %g gpm \n',Q2)\n", "\n", "disp('From psi_1=psi_2 we have delta p 2/(rho*D^2*N2^2)=delta p 1/(rho*D^2*N1^2)')\n", "delta_p2=delta_p1*((N2/N1)^2)\n", "printf(' The value of delta_p2 is equal to %g psig \n',delta_p2)\n", "\n", "disp('From pi_2=pi_1 we have P_s2=P_s1*((N2/N1)^3)')\n", "P_s2=P_s1*(N2/N1)^3\n", "printf(' The value of P_s2 is equal to %g hp \n',P_s2)\n", "\n", "disp('The efficiencies are same at the corresponding points,so E1=E2')\n", "E1=Q1*delta_p1*0.00223*144/(550*P_s1)\n", "printf(' The value of E1=E2 is equal to %g \n',E1)\n", "disp('Thus the efficiency is equal to 87.57%')" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.6: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_1S,page 29.\n", "Q1=18.2\n", "N1=1000\n", "N2=1500\n", "delta_p1=10.3\n", "P_s1=6\n", "\n", "Q2=Q1*N2/N1\n", "printf('\n The value of Q2 is equal to %g m^3/h',Q2)\n", "\n", "delta_p2=delta_p1*((N2/N1)^2)\n", "printf('\n The value of delta_p2 is equal to %0.1f bars',delta_p2)\n", "\n", "P_s2=P_s1*(N2/N1)^3\n", "printf('\n The value of P_s2 is equal to %g kW',P_s2)\n", "\n", "E1=((Q1/3600)*delta_p1*10^2)/(P_s1)\n", "printf('\n The value of E1=E2 is equal to %g ',E1)\n", "disp('Thus the efficiency is equal to 86.8%')" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.7: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_2E,page 30.\n", "P_ho=30//hydraulic output power\n", "Q=5//flow rate at best efficiency point\n", "g=32.2\n", "rho=1.938\n", "Hp=320\n", "N=600\n", "\n", "delta_pm=P_ho*550/Q\n", "printf('Value of discharge head P_m %g lb/ft^2',delta_pm)\n", "\n", "Hm=delta_pm/(rho*g)\n", "printf('\n Value of H_m=%0.2f ft',Hm)\n", "disp('From the similarity law, H_p/H_m=((Np/Nm)^2)*((Dp/Dm)^2)')\n", "\n", "//let x=Hp/Hm\n", "x=Hp/Hm\n", "printf(' H_p/H_m =%0.2f',x)\n", "disp('Thus (N_p/N_m)*(D_p/D_m) is equal to 2.46')\n", "disp('Also the flow rate Q_p/Q_m=(N_p/N_m)*(D_p/D_m)^3')\n", "z=350/5//value of Qp/Qm\n", "printf(' Hence the value of Q_p/Q_m is equal to %g',z)\n", "disp('Thus D_p/D_m=5.33 ,N_p/N_m=0.461')\n", "//Let y=Np/Nm=0.461\n", "y=0.461\n", "N_m=N/y\n", "printf(' Thus N_m = %g rpm',N_m)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.8: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_2S,page 30.\n", "//The value given in the book for N_m is 1315,but on calculating the true value is found out to be 1304.35\n", "\n", "P_ho=22.4//hydraulic output power\n", "Q=0.14//flow rate at best efficiency point\n", "g=9.8\n", "rho=998\n", "H_p=97.5\n", "N=600\n", "\n", "delta_pm=P_ho/Q\n", "printf('Value of discharge head P_m %g kPa',delta_pm)\n", "\n", "H_m=delta_pm*10^3/(rho*g)\n", "printf('\n Value of H_m=%g m',H_m)\n", "disp('From the similarity law, H_p/H_m=((N_p/N_m)^2)*((D_p/D_m)^2)')\n", "\n", "//let x=Hp/Hm\n", "H_mr=16.3//rounded off value\n", "x=H_p/H_mr\n", "printf(' H_p/H_m =%0.2f',x)\n", "disp('Thus (N_p/N_m)*(D_p/D_m) is equal to 2.45')\n", "disp('Also the flow rate Q_p/Q_m=(N_p/N_m)*(D_p/D_m)^3')\n", "z=9.9/0.14//value of Qp/Qm\n", "printf(' Thus the value of Q_p/Q_m is %0.1f',z)\n", "disp('Thus D_p/D_m=5.4 ,N_p/N_m=0.46')\n", "//Let y=Np/Nm=0.461\n", "y=0.46\n", "N_m=N/y//where N=600 and y=0.46 \n", "printf(' Hence N_m = %g rpm',N_m)//value given in the book is 1315,but on calculating the true value is found out to be 1304.35" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2.9: DA.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clear all; clc;\n", "//This numerical is Ex 2_3E,page 31.\n", "\n", "N=1500\n", "E=0.74\n", "Q=250*0.00223//0.00223 is conversion factor\n", "printf('Q is equal to %g',Q)\n", "H=18\n", "g=32.2\n", "Q_o=250//before converting Q\n", "\n", "disp('From the dimensional specific speed (N_s) and fig2.1 , we select a Francis type pump and efficiency is estimated to be equal to 74%')\n", "\n", "N_s=N*(Q_o^0.5)/(H^0.75)\n", "printf('\n N_s is equal to %0.0f rpm(gpm^0.5)/(ft^0.75)',N_s)\n", "disp('To find the approximate size,Figure 2.2 has to be used')\n", "\n", "omega=N*%pi/30\n", "printf('\n omega is equal to %0.0f',omega)\n", "\n", "omega_s=omega*(Q^0.5)/((g*H)^0.75)\n", "printf('\n omega_s is equal to %0.4f',omega_s)\n", "\n", "disp('From figure 2.2, it is obtained that delta_s=3.1')\n", "D=(3.1*(Q^0.5))/((g*H)^0.25)\n", "printf('\n Hence D is equal to %0.3f ft',D)\n", "disp('Hence D is equal to 5.7 in ')\n", "" ] } ], "metadata": { "kernelspec": { "display_name": "Scilab", "language": "scilab", "name": "scilab" }, "language_info": { "file_extension": ".sce", "help_links": [ { "text": "MetaKernel Magics", "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" } ], "mimetype": "text/x-octave", "name": "scilab", "version": "0.7.1" } }, "nbformat": 4, "nbformat_minor": 0 }