Activity responsible: Dr. Giuseppe
Address: ENEA C.R. Casaccia,Energy Department, Institute of Thermal
Fluid Dynamics, Via Anguillarese 301 (S.P. 092), 00060 S. M. di Galeria
Phone: +39 06 3048.4567 Fax: +39 06 3048.3026
Objectives of this experimental activity are here summarised:
- to obtain extensive heat transfer data (in Single Phase convection
end Two-Phase flow boiling) over large parameter ranges of refrigerants
flow in microtubes
- to obtain extensive pressure drop data of refrigerants flow in microtubes
- to verify heat transfer correlations in microtubes configuration
- to verify pressure drop correlations in microtubes.
facility - Test loop
The test loop, called MISHTRA (Micro Scale Heat TRAnsfer) has been designed
and built with with the following characteristics:
||Flow rate: up to 100 L/h
||Pressure: up to 30 bar
||Temperature: up to 150 °C
||DC power: up to 50 V and 1500 A.
Experimental facility - Test section
Because the tested tubes are relatively small, direct measurement of
thermal-hydraulic parameters is difficult and is subjected to large error.
Therefore, in order to obtain reasonable measurements, 6 microtubes, each
having the same diameter and length, are put together to form the test
section, as shown in the picture.
At present, indirect heating of the test micropipes has been set up using
condensing steam, in order to have a direct evaluation of the wall temperature
(without thermocouples soldered on the microtubes surface) and thus the
heat transfer coefficient. The experimental programme is carried out on
the MISHTRA facility.
- Test matrix
At present, experiments are focused on single phase pressure drop and
heat transfer with the following test parameters range:
D = 0.06, 0.13, 0.25 and 0.50 mm
Z = 0.1 m
U = 0.25 8.0 m/s
P = 20 30 bar
Tin = 20 80 °C
Flow direction: horizontal
||Compact and miniature heat exchangers
||Refrigeration and air conditioning systems