Numerical and Experimental Analysis of Transient Flow in Roots Blower

Sun, Shuaihui; Kovačević, Ahmed; Brücker, Christoph; Leto, Angelo; Singh, Gursharanjit; Ghavami, Mohsen

doi:10.1088/1757-899x/425/1/012024

Cited by 9 publications

(11 citation statements)

References 12 publications

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“…The double-pulse laser (K) and double shutter camera (M) with the resolution of 2048 × 2048 pixels were used to take every pair of images at a short interval of 2-50 µs that was depended on the maximum particle velocity in the flow field. The equipment used for measurements was introduced in detail in the previously published paper by the authors [9,25,26]. For the measurement of gap flow field, following changes were made to the test set-up: Firstly, the microscope lens Model K2 (Infinity photo-optical, Centennial, CO, USA) was equipped on the double-shutter camera to magnify the tip gap (see Figure 3).…”

Section: Experimental Setup and Data Processingmentioning

confidence: 99%

“…As the tip gap has been calibrated, the casing to rotor conformal grids for the moving rotor domain were regenerated using in-house grid generation software SCORG v5.7 [10][11][12] with tip gap of 0.4 mm. The stationary meshes in the fluid domains for inlet and outlet chambers and pipe were generated in ANSYS Mesh [9]. Then the grid independence study was conducted on rotor grids.…”

Section: Grid Generation and Grip Independence Studymentioning

confidence: 99%

“…Roots blowers do not have internal compression, as the volume of the chamber remains constant while rotating. The increase of the pressure is caused by the backflow from the high-pressure side [8,9]. There are three kinds of gaps in Roots blower: the tip gap, the interlobe gap and the axial gap.…”

Section: Introductionmentioning

confidence: 99%

“…However, as the screw machines have the helical rotors that limit optical access to the flow field, the quantitative velocity values in working chamber domains and gap domains cannot be obtained. Sun et al [9,25] and Singh et al [26] measured the velocity in the working chamber of a Roots blower with straight lobes using optical methods and compared the unsteady simulated main flow fields with the PIV test results. The three-dimensional and unsteady nature of the flow field was illustrated and the leakage flows through the three gaps were discussed.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and Numerical Investigation of Tip Leakage Flows in a Roots Blower

Sun

Singh

Kovačević

et al. 2020

Designs

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Computational fluid dynamics (CFD) can help in understanding the nature of leakage flow phenomena inside the rotary positive displacement machines (PDMs). However, due to the lack of experimental results, the analysis of leakage flows in rotary PDMs by CFD has not yet been fully validated. Particle image velocimetry (PIV) tests with a microscopic lens and phase-lock were conducted to obtain the velocity field around the tip gap in an optical Roots blower. The three-dimensional unsteady CFD model of the Roots blower with the dynamic grids generated by Screw Compressor Rotor Grid Generation (SCORG) was established to predict the gap flow under the same operating conditions. The images obtained by the PIV tests were analyzed and some factors which compromise the quality of test results in the gap flow were identified, such as reflections and transparency of the window. The flow fields obtained by CFD have the same flow pattern and velocity magnitude as the experimental results in the majority of observed regions but overestimate the leakage flow velocity. The CFD results show a vortex induced by the leakage flow in the downstream region of the gap. The flow losses in the tip gap mainly happen at the entrance upstream of the gap. Finally, some suggestions for future work are discussed.

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Section: Experimental Setup and Data Processingmentioning

confidence: 99%

Section: Grid Generation and Grip Independence Studymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental and Numerical Investigation of Tip Leakage Flows in a Roots Blower

Sun

Singh

Kovačević

et al. 2020

Designs

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“…The massive usage of these machines and regulations aiming to more efficient usage of energy [9] led researchers to look into the design phase and the operation analysis of screw-machines in order to maximize its efficiency. Analytical [10], experimental [11] and computational [12,13] analyses have been proposed in the literature in order to understand the fluid-dynamics inside the machines.…”

Section: Introductionmentioning

confidence: 99%

CFD Simulations of Single- and Twin-Screw Machines with OpenFOAM

Casari

Fadiga

Pinelli

et al. 2020

Designs

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Over the last decade, Computational Fluid Dynamics (CFD) has been increasingly applied for the design and analysis of positive displacement machines employed in vapor compression and power generation applications. Particularly, single-screw and twin-screw machines have received attention from the researchers, leading to the development and application of increasingly efficient techniques for their numerical simulation. Modeling the operation of such machines including the dynamics of the compression (or expansion) process and the deforming working chambers is particularly challenging. The relative motion of the rotors and the variation of the gaps during machine operation are a few of the major numerical challenges towards the implementation of reliable CFD models. Moreover, evaluating the thermophysical properties of real gases represents an additional challenge to be addressed. Special care must be given to defining equation of states or generating tables and computing the thermodynamic properties. Among several CFD suite available, the open-source OpenFOAM tool OpenFOAM, is regarded as a reliable and accurate software for carrying out CFD analyses. In this paper, the dynamic meshing techniques available within the software as well as new libraries implemented for expanding the functionalities of the software are presented. The simulation of both a single-screw and a twin-screw machine is described and results are discussed. Specifically, for the single-screw expander case, the geometry will be released as open-access for the entire community. Besides, the real gas modeling possibilities implemented in the software will be described and the CoolProp thermophysical library integration will be presented.

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Influence of rotor speed, discharge pressure, and clearance size on the unsteady flow dynamics and heat interaction of roots blower

Bhuyan

Ghosh

2021

J Braz. Soc. Mech. Sci. Eng.

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Numerical and Experimental Analysis of Transient Flow in Roots Blower

Cited by 9 publications

References 12 publications

Experimental and Numerical Investigation of Tip Leakage Flows in a Roots Blower

Experimental and Numerical Investigation of Tip Leakage Flows in a Roots Blower

CFD Simulations of Single- and Twin-Screw Machines with OpenFOAM

Influence of rotor speed, discharge pressure, and clearance size on the unsteady flow dynamics and heat interaction of roots blower

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