Saturation temperature effects on heat transfer performance of a falling film evaporator using enhanced tubes
Tutor / Supervisor
Thome, J.R.
Student
Alonso Acuña, Andreu
Document type
Master thesis (pre-Bologna period)
Date
2010
rights
Open Access
Publisher
École Polytechnique Fédérale de Lausanne
UPCommons
Abstract
In this work, the existing LTCM falling lm facility was utilized to perform
falling lm evaporation measurements on a vertical row of horizontal tubes.
The enhanced boiling tube, Wolverine Turbo-B5, was tested using R-134a
and R-236fa. The tests were carried out at di erent saturation temperatures
of: 7.5 C, 10 C, 12.5 C, 15 C, 17.5 C, 20 C, 22.5 C, 25 C, 27.5 C and 30 C
adding them to the existing 5 C saturation temperature in the database
from previous work. All the tests were carried out with liquid lm Reynolds
numbers ranging from 0 to 3000, and nominal heat
uxes of 20, 40 and
60 kW/m2. The experimental results for all temperatures are compared
with the current prediction method of Christians (2010). The e ects of
the di erent saturation temperatures on the heat transfer coe cient were
analyzed and compared for R-134a and R-236fa. Pool boiling heat transfer
coe cients were measured in the LTCM pool boiling facility to obtain the
falling lm multiplier Kff (Falling lm heat transfer coe cient relative to
pool boiling coe cient at the same heat
ux). These tests were carried out
at 20 C and 30 C for both R-134a and R-236fa. Finally an uncertainty
analysis of the refrigerant lm Reynolds number was carried out in order
to quantify the error in its calculation and a new lter for the experimental
data was proposed.
Participating teacher
- Thome, J.R.