Automated car transmissions have high demands of power, reliability, low fuel consumption and low noise emissions. On the one hand, for most of these requirements a hydraulic, positive displacement pump is a suitable power supply. This kind of pump is able to provide high power, high reliability and lubrication of the system. Therefore, positive displacement pumps, especially rotary vane pumps, are often applied as power supplies in automated transmissions [
1,
2]. On the other hand, mechanically driven transmission pumps typically lead to an increased fuel consumption and to high noise emissions.
Nowadays, rising demands for improved vehicle acoustics and lower noise emissions of other components, lead to the fact that often the pump is dominant in the acoustic characteristic of hydraulic systems [
3,
4,
5,
6,
7,
8]. There are different ways to enhance the acoustic characteristics of a pump. One approach is e.g., to change the excitation frequencies by asymmetric spacing or to reduce the radiated noise by structural changes [
3,
9]. Another approach is to directly reduce the noise sources in the flow of the pump. In general, to reduce the noise radiation of a pump, a fundamental knowledge of the noise source mechanisms and the system dynamic behavior is mandatory [
10,
11,
12]. To identify the source mechanisms of noise in the flow of the pump, a coupled CFD-FEM approach is chosen. The pump investigated in this work is a Bosch rotary vane pump for transmission applications with a displacement volume of 11.1 cm
3/rev. The external dimension of the housing are 70 mm in axial direction with a diameter of 110 mm. This rotary vane pump is pictured in
Figure 1. In this figure, the suction port (left picture blue part) and the delivery port (left picture red part) are spatially separated. Fluid is conveyed from the suction port, through the inlet (1) and the injector (2), to the delivery port and the outlet (3) by a set of pressure sealed displacement chambers (7). These chambers are formed by the static cam ring part (A), the static inner pump surfaces, the rotating rotor (B) and by the vanes (C), which are able to slide in and out of the rotor in radial direction. These components are pictured in
Figure 1 on the right. The kinematics of the vanes is determined by the shape of the cam ring. The back vane notch (6) which is connected to the high pressure section ensures that the vanes slide along the cam ring. During the suction process the volume of a displacement chamber is increasing which leads to an inflow in the displacement chamber at the suction ports (4). Subsequently, the displacement chamber disconnects from the suction port and hence, is neither connected to the suction nor to the delivery port (5). In this phase, the volume of the displacement chamber decreases slightly, leading to a pressure rise in the displacement chamber. This so called pre-compression is already enhancing the pressure level and therefore reduces the pressure surges arising from the connection of a displacement chamber with low pressure to the delivery port with high pressure. Additionally, to ensure a smoother transition, grooves are implemented at the delivery port. These grooves connect the delivery port and the next displacement chamber, leading to a smoother volume change and hence, help to avoid high pressure surges. The optimal size and shape of these grooves is depending on the density and viscosity of the oil and the actual operating speed of the pump [
13]. If the displacement chamber passes the groove and fully connects to the delivery port, the vane slides further back into the rotor. This decreases the volume of the displacement chamber leading to a fluid flow out of the chamber. The investigated pump is an asymmetric vane pump with two suction and two delivery ports. The stroke of the pump is slightly different for both delivery ports. Therefore, the pump can provide two different flow rates. The suction and delivery ports are located transversely and lead to a partly compensation of flow forces. Nevertheless, this working principle leads to flow and pressure pulsations, which excite enclosing structural elements and cause noise radiation of the pump [
7,
14,
15]. A combined CFD-FEM approach is applied to identify which flow induced effects are crucial for the noise radiation of the pump. There are a couple of studies focusing on noise radiation of pumps. In Ref. [
16] the authors investigate the fluid-borne sound of an axial piston pump by the use of a coupled 1D-3D simulation approach. The flow is modeled in a 1D simulation in AmeSim and a 3D FEM/BEM model in Virtual.Lab is used to predict noise sources and transmission paths. A similar approach is used by [
8,
11,
12,
15]. Here, the noise radiation of a gear pump is simulated using a lumped parameter model along with an FEM/BEM model. The coupling of a 3D-CFD model and an FEM/BEM model to predict the flow induced pressure pulsations and vibrations of a centrifugal pump is assessed in [
17,
18]. For rotary vane pumps a study using a coupled approach to analyze the structural forces acting on the rotor and vanes is presented by [
19] using a 3D CFD simulation of the flow in Ansys Fluent along with Ansys Mechanical. However, there is no study to predict the fluid induced vibrations and noise radiation of a rotary vane pump using a 3D-CFD model in combination with a FEM/BEM-based model.
For this purpose, in this work the flow in the pump is analyzed using a 3D-CFD simulation model build up in the commercial software STAR-CCM+. The results of this CFD model have been validated against displacement chamber pressure measurements in [
20]. Based on these results, the present paper focuses on the data transfer between the simulations and the vibroacoustic analysis. Therefore, the pressure field of this CFD simulation is mapped to a FEM grid. The pressure field is chosen, because it is assumed to be the main source in the flow for the pump’s noise radiation. Subsequently, the data transfer and processing are investigated and a vibroacoustic simulation is performed in the frequency domain. The vibroacoustic simulation results are compared to acceleration and sound pressure level measurements of the pump, which have been performed in a hemi-anechoic room.