Experiment Heat Exchanger Hot Steam Shell
Budget: $10 – $30 USD
2a. Provide plots to illustrate the effect of nominal tube size, the velocity of the liquid at the
entrance of the tube, and the steam pressure to the shell on the overall heat-transfer
coefficient (in W/(m2·K)) for the steam-heated exchangers.
2c. Apply least-squares analysis at the actual conditions of the trials to determine the parameters
of an interaction model:
ŷ = b0 + b1 X1 + b2 X2 + b3 X3 + b12 X1 X2 + b13 X1 X3 + b23 X2 X3 + b123 X1 X2 X33
Where ŷ = overall heat-transfer coefficient (in W/(m2·K))
X1 = nominal tube size (coded)
X2 = velocity of the liquid at the entrance of the tube (coded)
X3 = steam pressure to the shell (coded)
Estimate the standard error of each parameter and test for the statistical significance of each
parameter.
Note: A factorial analysis of the experimental values of the overall heat-transfer coefficient is not required.
2d. Predict the outlet tube temperature, the heat-transfer rate, and the overall heat-transfer
coefficient for each trial, at the same experimental conditions as those for the respective trial.
Apply semi-empirical correlations as a model to make the predictions, using a spreadsheet for
the calculations. Compare these predictions to the experimental results in terms of discrepancy and percent discrepancy as defined below.
Disc[Ttb] = [Ttb]pred − [Ttb]expt
PctDisc[Qt] = 100 × {[Qt]pred − [Qt]expt} / [Qt]expt
PctDisc[Uo] = 100 × {[Uo]pred − [Uo]exp}/ [Uo]expt
2f. 2f. Examine the possibility of distortion in the experimental results for the steam-heated
exchangers due to heat losses. That is, after the tube exits the covering of the shell, the hot
water in the tube might lose heat to the environment before it reaches the outlet temperature
probe.
From the measured value of the outlet tube temperature, estimate an adjusted experimental
value of outlet tube temperature. Use these adjusted experimental values to calculate adjusted
experimental values of Qt and Uo.
Note: This issue arises because the diameter of the temperature probe is larger than the inside
diameter of the tube.
Compare these adjusted experimental values to the predicted values. Design the summary
table similar to that for the prior objective.
entrance of the tube, and the steam pressure to the shell on the overall heat-transfer
coefficient (in W/(m2·K)) for the steam-heated exchangers.
2c. Apply least-squares analysis at the actual conditions of the trials to determine the parameters
of an interaction model:
ŷ = b0 + b1 X1 + b2 X2 + b3 X3 + b12 X1 X2 + b13 X1 X3 + b23 X2 X3 + b123 X1 X2 X33
Where ŷ = overall heat-transfer coefficient (in W/(m2·K))
X1 = nominal tube size (coded)
X2 = velocity of the liquid at the entrance of the tube (coded)
X3 = steam pressure to the shell (coded)
Estimate the standard error of each parameter and test for the statistical significance of each
parameter.
Note: A factorial analysis of the experimental values of the overall heat-transfer coefficient is not required.
2d. Predict the outlet tube temperature, the heat-transfer rate, and the overall heat-transfer
coefficient for each trial, at the same experimental conditions as those for the respective trial.
Apply semi-empirical correlations as a model to make the predictions, using a spreadsheet for
the calculations. Compare these predictions to the experimental results in terms of discrepancy and percent discrepancy as defined below.
Disc[Ttb] = [Ttb]pred − [Ttb]expt
PctDisc[Qt] = 100 × {[Qt]pred − [Qt]expt} / [Qt]expt
PctDisc[Uo] = 100 × {[Uo]pred − [Uo]exp}/ [Uo]expt
2f. 2f. Examine the possibility of distortion in the experimental results for the steam-heated
exchangers due to heat losses. That is, after the tube exits the covering of the shell, the hot
water in the tube might lose heat to the environment before it reaches the outlet temperature
probe.
From the measured value of the outlet tube temperature, estimate an adjusted experimental
value of outlet tube temperature. Use these adjusted experimental values to calculate adjusted
experimental values of Qt and Uo.
Note: This issue arises because the diameter of the temperature probe is larger than the inside
diameter of the tube.
Compare these adjusted experimental values to the predicted values. Design the summary
table similar to that for the prior objective.