1. Project Review – Engineering Calculations Project
Water jacket CFD simulation of the Volvo ED3568/Step3 compressor
Knorr-Bremse, EC/2009/xxxx
Strictly confidential
Templates deutsch_5. Oktober 2005

2. 1. Model geometry
RVP2
SVPG
SVPF
SCHD
RVP1
SVPH
SVPE
SVPD
SVPC
SCHC
SVPJ
SVPI
SSCD
SVPB
SVPK
SVPL
SSCC
SCHA
SVPA
SCC3
SCHB
RVP3
SCC2
SSCA
SCC1
RSCA
RSCB
SSCB
Reference surfaces and reference regions used in the simulations at the lower (left) and upper (right) part of the water jacket. The name of the surfaces (black) and regions (orange/red) are indicated.

3. 2. Mesh OUTLET Cylinder head Supercooling Valve plate Crankcase INLET
Finite element mesh of the water jacket geometry with nodes and tetrahedra elements. The names of the main parts of the water jacket are indicated

4. 3. Basic settings Solver: Ansys 11.0 / CFX5 Steady state simulation
Required accuracy for solver: 10-5
Boundary conditions:
Inlet mass flow rates: 2, 4, 6, 8 and 10 l min-1 (0.035, 0.070, 0.105, and kg s-1, respectively)
Reference pressure: 1 bar
Fluid properties:
Mixture: glycol-water (52-48%)
Operating temperature: 80°C
Density: 1045 kg m-3
Specific heat: 3490 J kg-1 K-1
Thermal conductivity: 0.39 W m-1 K-1
Dynamic viscosity: kg m-1 s-1
Molecular weight:

5. 4.1 Results with 2 l min-1 flow rate
Streamline patterns in the lower (crankcase and valveplate, left) and upper (supercooling and cylinder head, right) parts of the water jacket in the 2 l min-1 flow rate case.

6. 4.1 Results with 2 l min-1 flow rate
Pressure distribution in the lower (crankcase and valveplate, left) and upper (supercooling and cylinder head, right) parts of the water jacket in the 2 l min-1 flow rate case.

7. 4.2 Results with 4 l min-1 flow rate
Streamline patterns in the lower (crankcase and valveplate, left) and upper (supercooling and cylinder head, right) parts of the water jacket in the 4 l min-1 flow rate case.

8. 4.2 Results with 4 l min-1 flow rate
Pressure distribution in the lower (crankcase and valveplate, left) and upper (supercooling and cylinder head, right) parts of the water jacket in the 4 l min-1 flow rate case.

9. 4.3 Results with 6 l min-1 flow rate
Streamline patterns in the lower (crankcase and valveplate, left) and upper (supercooling and cylinder head, right) parts of the water jacket in the 6 l min-1 flow rate case.

10. 4.3 Results with 6 l min-1 flow rate
Pressure distribution in the lower (crankcase and valveplate, left) and upper (supercooling and cylinder head, right) parts of the water jacket in the 6 l min-1 flow rate case.

11. 4.4 Results with 8 l min-1 flow rate
Streamline patterns in the lower (crankcase and valveplate, left) and upper (supercooling and cylinder head, right) parts of the water jacket in the 8 l min-1 flow rate case.

12. 4.4 Results with 8 l min-1 flow rate
Pressure distribution in the lower (crankcase and valveplate, left) and upper (supercooling and cylinder head, right) parts of the water jacket in the 8 l min-1 flow rate case.

13. 4.5 Results with 10 l min-1 flow rate
Streamline patterns in the lower (crankcase and valveplate, left) and upper (supercooling and cylinder head, right) parts of the water jacket in the 10 l min-1 flow rate case.

14. 4.5 Results with 10 l min-1 flow rate
Pressure distribution in the lower (crankcase and valveplate, left) and upper (supercooling and cylinder head, right) parts of the water jacket in the 10 l min-1 flow rate case.

15. 5.1 Mass flow: Crankcase
At low inlet flow rate (Q0) the three surfaces show a similar contribution  the flow is well distributed
At higher Q0 the uppermost surface (SCC3) has a higher relative contribution
Area-normalized mass flow rates as the function of inlet flow rate at the reference surfaces in the crankcase

16. 5.2 Mass flow: Valve plate, SVP1
The mass flow rate at the SVPC surface remains low and decreases for higher Q0 values.
For higher Q0 more coolant flows into the regions above the valveplate
The whole area obtains ~55% of the whole inflowing coolant
Mass flow rates as the function of inlet flow rate at the reference surfaces in the valve plate / SVP1 region

17. 5.2 Mass flow: Valve plate, SVP2
The mass flow rate at the SVPF & SVPG depends strongly on Q0.
For higher Q0 more coolant flows into the regions above the valveplate (as for SVP1)
The whole area obtains ~45% of the whole inflowing coolant
Mass flow rates as the function of inlet flow rate at the reference surfaces in the valve plate / SVP2 region

18. 5.2 Mass flow: Valve plate, SVP3
The relative distribution of the flow in the „SVPI” and „SVPK” parallel chanels depends strongly on the flow velocity.
For higher Q0 the flow „changes lane”, and swithces from the „SVPI” track to „SVPK”  the cooling efficiency drops for the area aroung SVPI.
The whole area obtains ~45% of the whole inflowing coolant
Mass flow rates as the function of inlet flow rate at the reference surfaces in the valve plate / SVP3 region

19. 5.3 Mass flow: Supercooling
The relative contribution of the four reference surfaces to the overall massflow budget is almost constant for the different Q0-s.
Mass flow rates of the four surfaces are rather different (~4, 14, 18 and 26%of the total mass flow for the SSCA, -B, -C and -D surfaces, respectively).
The mass flow through SSCA is very low, indicating that the cooling through the related wall surfaces is insufficient.
Mass flow rates as the function of inlet flow rate at the supercooling surfaces.

20. 5.4 Mass flow: Cylinder head
The SCHA-SCHD and SCHB-SCHC surfaces pairs has identical mass flow rates (as expected from the geometry)
The relative contributions of the SCHA-SCHD and SCHB-SCHC surface pairs to the overall mass flow rate are 45% and 55%, respectively (slight imbalance)
Mass flow rates as the function of inlet flow rate at the reference surfaces in the cylinder head

21. 6. Streamline-critical regions
Streamline pattern in the first quater of the crankcase part, right after the inlet in the Q0 = 2 l min-1 (left) and 10 l min-1 (right) cases. In the 2 l min-1 case a turbulent region (separation bubble) is present. At higher Q0 the region the flow can hardly penetrate into this region.

22. 6. Streamline-critical regions
RSCA
RSCB 3 4 1 2
Magnidied view of the streamline pattern in the RSCB (left) and RSCA (right) parts of the super-cooling at Q0 = 10 l min-1.
RSCA: The flow can hardly penetrate into this region (see the low mass flow rates through SSCA as well), likely causing an unefficient cooling. Removal of the nooks can improve the behaviour.
RSCB: Almost the whole flow enters and leaves this regions through orifice #1, and the flow is very unefficient through orifice #2. Omitting the indenture between #1 and #2 (marked by 3) could improve the flow behaviour. The furthermost flat part of the structure should also be left out.

23. 6. Streamline-critical regions8 7 6 5
Streamline pattern in the upper part of the water jacket at Q0 = 2 l min-1 (left) and at 10 l min-1 (right) in the cylinder head. At Q0 = 2 l min-1 there are two regions (marked by red ellipses, #5 and #6) where the flow does not fill properly the whole domain in. At higher Q0 two other simiar zones form (#7 and #8).

24. 7. Summary
In the crankcase region a sepration bubble forms close to the inlet orifice, at the other parts the flow is relatively well distributed.
The flow in the valveplate is relatively well distributed, no major critical regions have been identified. However, there are some areas, where the cooling efficiency may decrease for higher inflow rates.
The RSCA and RSCB regions (supercooling) should be modified for a better flow distribution and for a more efficient cooling.
There are two small regions with an insufficient flow pattern in the cylinder head area at low inlet flow rates, and two more similar regions form for higher fluid velocities.