This may be a better address:
https://www.alfalaval.com/globalassets/documents/industries/chemicals/petrochemicals/business_case_transfer_line_exchangers_ppi00529en.pdf
The following links may show additional reasons:
https://www.alfalaval.com/globalassets/documents/industries/chemicals/petrochemicals/business_case_transfer_line_exchangers_ppi00529en
http://www.arvos-group.com/media/1167/tranfer-line-exchangers.pdf
If the flowing fluid is incompressible, with p (rho) as density, a Pitot tube would measure total local pressure or stagnation pressure pstag=p+1/2pv2, while a static gage would measure p. The difference of the readings is the velocity head. The units in this equation can be Pa or N/m2.
Just a counterintuitive curiosity, the kinematic viscosities of gases can be greater than those of lube oils.
http://www.engineeringtoolbox.com/dynamic-absolute-kinematic-viscosity-d_412.html
As I see it, and I may be mistaken, the thermal efficiency of a heat exchanger is generally expressed as the ratio of the actual heat transferred to the optimum heat transfer Qopt = UA (AMTD).
Each case has a different Qopt.
Us-w > 2 Uw-w
AMTD for steam-to water: (131+60)/2 = 95.5 °c...
Get hold of Fan Engineering, an Engineer's Handbook on Fans and Their applications.
Edited by Robert Jorgensen
Published by BUFFALO FORGE COMPANY, Buffalo, New York
The first equation gives the heat gain or loss of each of the heat exchanging streams.
The second equation gives the heat transferred in the heat exchanger.
It appears that the dash is not a negative sign but a simple hyphen.
Besides, kg/cm^2, as a measure of pressure, still appears on some eastern european manometers.
Steam at those conditions is slightly superheated.