# Numerical and Experimental Investigations to Assess the Impact of an Oil Jet Nozzle with Double Orifices on the Oil Capture Performance of a Radial Oil Scoop

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## Abstract

**:**

## 1. Introduction

^{6}mm·r/min, and that it is an effective way to solve the lubrication and cooling problems of high-speed bearings [1,2]. When under-race lubrication is used, bearing lubrication, friction heat generation, and temperature are no longer limiting factors for high-speed bearings [3,4]. The working process of under-race lubrication includes four stages: oil injection, oil capture, oil delivery, and lubrication and cooling. Due to structural and spatial limitations, it is difficult for the oil scoop to capture all the lubricant oil sprayed from the oil jet nozzle into the bearing, resulting in some rebound, fragmentation, and splash losses. Therefore, there is a problem with oil capture efficiency. Researchers have carried out a large number of numerical simulations and experimental studies on the internal flow and oil capture performance of under-race lubrication systems, aiming to reveal the complex oil–air two-phase flow mechanism of under-race lubrication and to find out the correlations between operating conditions, structural parameters, and oil capture performance.

## 2. Experimental Setup

## 3. Mathematical Modeling

#### 3.1. Computational Domain and Mesh

^{+}) of the first layer is less than 5. At the same time, to reduce the computational errors caused by the use of interpolation methods for flow information transfer between different computational domains, the mesh size consistency on both sides of the interface is ensured as much as possible.

#### 3.2. Two-Phase Flow and Turbulence Models

#### 3.3. Boundary Conditions and Fluid Properties

^{3}, a lubricant oil viscosity of 5 mm

^{2}/s, and a surface tension of 0.035 N/m.

#### 3.4. Model Validation

## 4. Results and Discussion

## 5. Conclusions

- (1)
- The variation trend of the typical test data is consistent with that of the numerical simulation results, which confirms the rationality of the experimental scheme and the effectiveness of the numerical model.
- (2)
- A double-orifice structure can significantly increase the amount of captured oil compared to the single orifice structure, but it still captures less than twice the amount of oil captured by the single-orifice structure. At the same time, the degree to which a double-orifice tandem structure can improve the oil capture efficiency of a radial oil scoop is very limited, and the maximum increase is only 6%. It is worth noting that improper design of the orifice spacing will reduce the oil capture efficiency, with a maximum reduction of up to 12%.
- (3)
- When the structure design of the oil jet nozzle or the installation space is limited and it is necessary to choose the double-orifice tandem structure, the orifice spacing should be determined based on a full evaluation of the effect of the orifice spacing and working parameters on the oil capture performance.

## Author Contributions

## Funding

## Data Availability Statement

## Conflicts of Interest

## References

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**Figure 5.**Comparison of the oil capture efficiency values obtained from the numerical simulations with the experimental results.

**Figure 6.**The variations in oil capture efficiency with changing orifice spacing under different oil supply pressures in a double-orifice tandem layout.

**Figure 7.**Oil–air two-phase distribution when the oil scoop blade cuts the oil jet in structures with different orifice spacing (Δp = 0.1 MPa, n = 2517 r/min).

**Figure 8.**Oil–air two-phase distribution when the oil scoop blade cuts the oil jet in structures with different orifice spacing (Δp = 0.4 MPa, n = 10,017 r/min).

**Figure 9.**Comparison between oil capture efficiency of double-orifice tandem layout structure and single-orifice structure under different working conditions.

**Figure 10.**Comparison of the captured oil of the double-orifice tandem layout structure and that of the single-orifice structure at different speeds.

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**MDPI and ACS Style**

Jiang, L.; Lyu, Y.; Li, Y.; Liu, Y.; Hou, Y.; Liu, Z.
Numerical and Experimental Investigations to Assess the Impact of an Oil Jet Nozzle with Double Orifices on the Oil Capture Performance of a Radial Oil Scoop. *Aerospace* **2023**, *10*, 1015.
https://doi.org/10.3390/aerospace10121015

**AMA Style**

Jiang L, Lyu Y, Li Y, Liu Y, Hou Y, Liu Z.
Numerical and Experimental Investigations to Assess the Impact of an Oil Jet Nozzle with Double Orifices on the Oil Capture Performance of a Radial Oil Scoop. *Aerospace*. 2023; 10(12):1015.
https://doi.org/10.3390/aerospace10121015

**Chicago/Turabian Style**

Jiang, Le, Yaguo Lyu, Yanjun Li, Yewei Liu, Yankun Hou, and Zhenxia Liu.
2023. "Numerical and Experimental Investigations to Assess the Impact of an Oil Jet Nozzle with Double Orifices on the Oil Capture Performance of a Radial Oil Scoop" *Aerospace* 10, no. 12: 1015.
https://doi.org/10.3390/aerospace10121015