1. HYDAC Filtertechnik GmbH
Reservoir Study
HYDAC Technology Corp.
James Cardillo
Brian Schreiber
HYDAC Filtertechnik GmbH
Dr. Alexander Wohlers

2. Overview Objectives Geometry Overview Investigations
Sloshing Investigation
Baseline CFD Simulation
Experimental Investigation
De-aeration Investigation
Baseline Case
Optimized Case
Conclusion and Discussion of Results

3. Leakage through flange.
Objectives
Customer added drain line to integrated breather – New design to remove
Primary Objective:
Customer reports that leakage
is occurring through the filter
bolting flange and the integrated
breather.
The primary objective is to provide a solution to the customer so that this problem can be fixed.
Leakage through flange.
It has been hypothesized that this leakage is occurring as a result of fluid sloshing.
Secondary Objective:
The HYDAC solution should also optimize the tank for de-aeration in a way that can provide the customer with better oil quality, better efficiency, and thus additional savings.
A full CFD investigation of the tank de-aeration performance will be used to provide a solution.

4. Geometry Overview The reservoir tank model is shown below.
Fluid Volume
Oil Level
Return Flow:
25 GPM
Suction Flow:
20 GPM

5. Sloshing Investigation : Baseline CFD Simulation
(Snapshot of Critical Behavior)
Proposed Leakage
Gap
T = 2.3 sec.

6. Sloshing Investigation :
It was hypothesized that leakage through the integrated breather on the competitor’s filter was a result of intense fluid sloshing in the tank.
Simulations and experiments show sloshing is at potentially harmful levels.

7. De-aeration Investigation
The tank was investigated from the standpoint of de-aeration performance and an optional optimization is suggested.

8. De-aeration Investigation: Baseline Case
T = 1.75 sec.
Short Circuit to suction port. Very dangerous aeration behavior.

9. De-aeration Investigation: Optimized Case
The desired flow pattern is shown by the yellow vectors.
Opening moved to the top to force dispersed air towards the surface
Inlet nozzle to increase residence time.
Wall extended to block short circuit

10. De-aeration Investigation: Optimized Case
T = 1.75 sec.
Short circuit has been eliminated. No air is introduced to the suction port.

11. De-aeration Investigation: Optimized Case
T ≈ 14.5 sec.
Air is introduced to the suction port at 14.5 seconds.

12. De-aeration Investigation:
Baseline
Optimized
Time for air to reach suction port:
1.75 sec.
14.5 sec.
Time for concentrated air to
reach suction port:
15 sec.
> 30 sec.
Air concentration at suction port
after 30 sec:
10.6 %
3.5 %

13. Conclusion and Discussion
The experimental and numerical investigations show sloshing at un-preferred levels when the tank is in motion.
The de-aeration performance was evaluated using numerical tools. An improvement was proposed which uses an integrated HYDAC filter and some tank optimizations.

14. Extra Information to follow: Optional Slosh Protection for the Filter

15. Simulation Studies: Sloshing Simulation: Optimized
This piece has been added as a safeguard against the splashing during acceleration/braking (high speed turning on the other axis has not been accounted for). In this way, the leakage through the filter flange can be minimized.
These changes are part of the de-aeration optimization and will be discussed later.

16. Simulation Studies: Sloshing Simulation: Optimized
No Leakage
T = 2.3 sec.

17. Simulation Studies: Sloshing Simulation: Comparison
Baseline
Optimized
T = 2.3 sec.