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You have been assigned to collect thermodynamic data for a
Chapter 7, Problem 7.27(choose chapter or problem)
You have been assigned to collect thermodynamic data for a new liquid product your company is about to begin manufacturing and you decide to use a continuous-flow technique to generate a correlation of fl versus T. You wrap an electrical heating tape around a pipe, cover the tape with a thick layer of insulation, pump the liquid through the pipe at the rate of 228 g/min, and adjust the power input to the heating tape with a variable resistor. For each resistance setting, you record the power input and the temperature of the liquid at the pipe outlet. You multiply the power input by a correction factor of 0.94 to determine the rate of heat input to the liquid. The entering fluid temperature remains at 25C throughout the experiment. The following data are taken: 25.0 26.4 27.8 29.0 32.4 Heat Input to the Liquid (W) 0.0 17.0 35.3 50.9 94.4 Student Workbook heat Encyclopedia Equipment exchanger (a) Generate a table of fl(J/g) versus TCC), taking 25C and 1 atm as the reference state. (b) Fit a line to the data (either graphically or by the method of least squares) to determine the coefficient b of an expression of the form fl = beT - 25). (c) Estimate the heat input required to raise 350 kg/min of the liquid from 20C to 40e. (d) The correction factor of 0.94 accounts for the fact that the rate of energy input to the heating tape is somewhat greater than the rate of energy input to the liquid. Where does the additional energy go? (There are several answers.)
Questions & Answers
QUESTION:
You have been assigned to collect thermodynamic data for a new liquid product your company is about to begin manufacturing and you decide to use a continuous-flow technique to generate a correlation of fl versus T. You wrap an electrical heating tape around a pipe, cover the tape with a thick layer of insulation, pump the liquid through the pipe at the rate of 228 g/min, and adjust the power input to the heating tape with a variable resistor. For each resistance setting, you record the power input and the temperature of the liquid at the pipe outlet. You multiply the power input by a correction factor of 0.94 to determine the rate of heat input to the liquid. The entering fluid temperature remains at 25C throughout the experiment. The following data are taken: 25.0 26.4 27.8 29.0 32.4 Heat Input to the Liquid (W) 0.0 17.0 35.3 50.9 94.4 Student Workbook heat Encyclopedia Equipment exchanger (a) Generate a table of fl(J/g) versus TCC), taking 25C and 1 atm as the reference state. (b) Fit a line to the data (either graphically or by the method of least squares) to determine the coefficient b of an expression of the form fl = beT - 25). (c) Estimate the heat input required to raise 350 kg/min of the liquid from 20C to 40e. (d) The correction factor of 0.94 accounts for the fact that the rate of energy input to the heating tape is somewhat greater than the rate of energy input to the liquid. Where does the additional energy go? (There are several answers.)
ANSWER:Problem 7.27You have been assigned to collect thermodynamic data for a new liquid product your companyis about to begin manufacturing and you decide to use a continuous-flow technique to generatea correlation of versus T. You wrap an electrical heating tape around a pipe, cover the tapewith a thick layer of insulation, pump the liquid through the pipe at the rate of 228 g/min, andadjust the power input to the heating tape with a variable resistor. For each resistance setting,you record the power input and the temperature of the liquid at the pipe outlet. You multiply thepower input by a correction factor of 0.94 to determine the rate of heat input to the liquid. Theentering fluid temperature remains at 25°C throughout the experiment. The following data aretaken:(a) Generate a table of (J/g) versus T°C), taking 25°C and 1 atm as the reference state.(b) Fit a line to the data (either graphically or by the method of least squares) to determine thecoefficient b of an expression of the form = b(T - 25).(c) Estimate the heat input required to raise 350 kg/min of the liquid from 20°C to 40°C(d) The correction factor of 0.94 accounts for the fact that the rate of energy input to the heatingtape is somewhat greater than the rate of energy input to the liquid. Where does the additionalenergy go (There are several answers.) Step-by-step solution Step 1 of 8 ^(a)The specific enthalpy, is defined as the ratio of rate of heat added, to the mass flow rate ofliquid, . Write the mathematical equation as follows: ………(1)Mass flow rate, is equal to 228 g/min.Substitute 228 g/min for in equation (1) to obtain a relation between and .\n