Experimental pressure-drop data obtained in a series of tests in which water was heated while flowing through an electrically heated tube of 0.527 in. ID, 38.6 in. long, are tabulated below

Isothermal pressure-drop data for the same tube are given in terms of the dimensionless friction factor f = (??p/ρ u2) (2D/L)gc and Reynolds number based on the pipe diameter, ReD = u D/v = 4m/πDμ below.

By comparing the isothermal with the nonisothermal friction coefficients at similar bulk Reynolds numbers, derive a dimensionless equation for the non-isothermal friction coefficients in the formf = constant × Redn (μ s /μb)mwhere μs = viscosity at surface temperatureμb = viscosity at bulk temperaturen and m = empirical constants.GIVENWater flowing through a tubeIsothermal and nonisothermal pressure drop data given aboveThe dimensionless friction factor (f) = (??p/ρ u2 ) (2D/L)gcReynolds number (ReD) = 4 m/πD μInside tube diameter (D) = 0.527 in = 0.0439 ftTube length (L) = 38.6 in = 3.22 ft

From Appendix 2, Table 13, forwater

Transcribed Image Text:

Tube Surface Temp T, (°F) 126 202 219 248 283 Pressure Drop with Heat Transfer Ap Fluid Bulk Mass Flow Rate (Ib/sec) 3.04 2.16 1.82 3.06 in Temp T, (psi) (°F) 9.56 4.74 3.22 8.34 4.45 90 114 97 99 107 2.15