ATLAS CO2 Cooling
- Microchannels Analysis-
João Noite PH-CMX-DS
Boundary Conditions
• 2-Phase correlation is valid for heat fluxes within the range of 1.8 to
46kW/m2 and tube diameters of 0.6 to 10mm
• Sensor heat flux = 0.1W/cm2 = 1kW/m2
• Sensor dimensions = 20 x 20mm
• Channel height = 50μm
• Channel width = 50μm
• Channel equivalent diameter = 0.056mm
• Longest channel length = 77.765mm
• Shortest channel length = 43.765mm
João Noite PH-CMX-DS
2
Boundary Conditions
Short restriction
= 6.334 mm
Longest channel: 77.765 mm
Shortest channel: 43.765 mm
Long restriction
= 10.759 mm
João Noite PH-CMX-DS
3
Longest Channel
m = 0.0002g/s | Qtotal = 0.0110W | P in = 19.75Bar | Tin = -20.00°C | dP = 0.05Bar | x out = 0.19
ATLAS Micro Channels | m = 0.0002g/s | Q total = 0.0110W | dP = 0.05Bar | dT = -0.69°C
-40°C -30°C -20°C -10°C 0°C
Theory Wall Temperature
Theory CO2 Temperature
70
Theory CO2 Pressure
60
19.72
-19
Pressure [Bar]
19.74
Pressure [Bar]
-18
10°C
20°C
30°C
50
40
30
20
10
-20
19.7
100
150
200
250
Enthalpy [kJ/kg]
300
350
G = 80kg/m2.s | q = 0.80kW/m 2 | Psat = 19.70Bar | x out = 0.19 | x dryout = 0.94
-21
0
0.01
0.02
0.03
0.04
0.05
Length [m]
0.06
0.07
0.08
19.68
500
Mass Velocity [kg/m 2.s]
Temperature [°C]
80
19.76
-17
400
300
200
100
0
João Noite PH-CMX-DS
0
0.1
0.2
0.3
0.4
0.5
0.6
Vapor Quality
0.7
0.8
0.9
1
4
Shortest Channel
m = 0.0002g/s | Qtotal = 0.0078W | P in = 19.77Bar | Tin = -20.00°C | dP = 0.08Bar | x out = 0.13
ATLAS Micro Channels | m = 0.0002g/s | Q total = 0.0078W | dP = 0.08Bar | dT = -0.84°C
-40°C -30°C -20°C -10°C 0°C
Theory Wall Temperature
Theory CO2 Temperature
70
Theory CO2 Pressure
60
19.72
-19
Pressure [Bar]
19.74
Pressure [Bar]
-18
10°C
20°C
30°C
50
40
30
20
10
-20
19.7
100
150
200
250
Enthalpy [kJ/kg]
300
350
G = 80kg/m2.s | q = 1.01kW/m 2 | Psat = 19.70Bar | x out = 0.13 | x dryout = 0.93
-21
0
0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05
Length [m]
19.68
500
Mass Velocity [kg/m 2.s]
Temperature [°C]
80
19.76
-17
400
300
200
100
0
João Noite PH-CMX-DS
0
0.1
0.2
0.3
0.4
0.5
0.6
Vapor Quality
0.7
0.8
0.9
1
5
Longest channel with 10x20μm restriction
ATLAS Micro Channels | m = 0.0002g/s | Q total = 0.0110W | dP = 1.19Bar | dT = -0.68°C
-17
m = 0.0002g/s | Qtotal = 0.0110W | P in = 20.89Bar | Tin = -20.00°C | dP = 1.19Bar | x out = 0.19
80
21
Theory Wall Temperature
Theory CO2 Temperature
-17.5
-40°C -30°C -20°C -10°C 0°C
20.4
20.2
Pressure [Bar]
-18.5
Pressure [Bar]
50
40
30
20
10
20
100
-20.5
0
0.01
0.02
0.03
0.04
0.05
Length [m]
0.06
0.07
0.08
150
200
250
Enthalpy [kJ/kg]
300
350
G = 80kg/m2.s | q = 0.80kW/m 2 | Psat = 19.70Bar | x out = 0.19 | x dryout = 0.94
19.8
19.6
500
Mass Velocity [kg/m 2.s]
Temperature [°C]
20.6
-20
30°C
60
-18
-19.5
20°C
20.8
Theory CO2 Pressure
-19
10°C
70
400
300
200
100
0
João Noite PH-CMX-DS
0
0.1
0.2
0.3
0.4
0.5
0.6
Vapor Quality
0.7
0.8
0.9
1
6
Shortest channel with 10x20μm restriction
ATLAS Micro Channels | m = 0.0002g/s | Q total = 0.0078W | dP = 1.87Bar | dT = -0.84°C
80
22
-40°C -30°C -20°C -10°C 0°C
70
Theory CO2 Pressure
60
-18
Pressure [Bar]
Theory Wall Temperature
Theory CO2 Temperature
21
Pressure [Bar]
-20
10°C
20°C
30°C
50
40
30
20
20
10
100
150
200
250
Enthalpy [kJ/kg]
300
350
G = 80kg/m2.s | q = 1.01kW/m 2 | Psat = 19.70Bar | x out = 0.13 | x dryout = 0.93
-22
0
0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05
Length [m]
19
500
Mass Velocity [kg/m 2.s]
Temperature [°C]
-16
m = 0.0002g/s | Qtotal = 0.0078W | P in = 21.57Bar | Tin = -20.00°C | dP = 1.87Bar | x out = 0.13
400
300
200
100
0
João Noite PH-CMX-DS
0
0.1
0.2
0.3
0.4
0.5
0.6
Vapor Quality
0.7
0.8
0.9
1
7
Decrease shortest channel restriction length to match ΔP
ATLAS Micro Channels | m = 0.0002g/s | Q total = 0.0078W | dP = 1.19Bar | dT = -0.87°C
-17
-17.5
m = 0.0002g/s | Qtotal = 0.0078W | P in = 20.89Bar | Tin = -20.00°C | dP = 1.19Bar | x out = 0.14
80
21
Theory Wall Temperature
Theory CO2 Temperature
-40°C -30°C -20°C -10°C 0°C
20.4
20.2
Pressure [Bar]
-18.5
Pressure [Bar]
50
40
30
20
10
20
100
-20.5
0
0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05
Length [m]
10x20μm Restriction:
Shortest channel length = 47.524mm
Restriction length = 7mm
150
200
250
Enthalpy [kJ/kg]
300
350
G = 80kg/m2.s | q = 0.93kW/m 2 | Psat = 19.70Bar | x out = 0.14 | x dryout = 0.93
19.8
19.6
500
Mass Velocity [kg/m 2.s]
Temperature [°C]
20.6
-20
30°C
60
-18
-19.5
20°C
20.8
Theory CO2 Pressure
-19
10°C
70
400
300
200
100
0
João Noite PH-CMX-DS
0
0.1
0.2
0.3
0.4
0.5
0.6
Vapor Quality
0.7
0.8
0.9
1
8