Experimental and Numerical Investigation of the Flow Inside the Return Channel of a Centrifugal Process Compressor

This paper presents the first detailed experimental performance data for a new centrifugal process compressor test rig. Additional numerical simulations supported by extensive pressure measurements at various positions allow an analysis of the operational and loss behavior of the entire stage and its components. The stage investigated is a high flow rate stage of a single-shaft, multistage compressor for industrial applications and consists of a shrouded impeller, a vaneless diffuser, a U-bend, and an adjoining vaned return channel. Large channel heights due to high flow rates induce the formation of highly three-dimensional flow phenomena and thus enlarge the losses due to secondary flows. An accurate prediction of this loss behavior by means of numerical investigations is challenging. The published experimental data offer the opportunity to validate the used numerical methods at discrete measurement planes, which strengthens confidence in the numerical predictions. CFD simulations of the stage are initially validated with global performance data and extensive static pressure measurements in the vaneless diffuser. The comparison of the pressure rise and an estimation of the loss behavior inside the vaneless diffuser provide the basis for a numerical investigation of the flow phenomena in the U-bend and the vaned return channel. The flow acceleration in the U-bend is further assessed via the measured two-dimensional pressure field on the hub wall. The upstream potential field of the return channel vanes allows an evaluation of the resulting flow angle. Measurements within the return channel provide information about the deceleration and turning of the flow. In combination with the numerical simulations, loss mechanisms can be identified and are presented in detail in this paper.

Experimental and Numerical Investigation of the Flow Inside the Return Channel of a Centrifugal Process Compressor

This paper presents the first detailed experimental performance data for a new centrifugal process compressor test rig. Additional numerical simulations supported by extensive pressure measurements at various positions allow an analysis of the operational and loss behavior of the entire stage and its components. The stage investigated is a high flow rate stage of a single-shaft, multistage compressor for industrial applications and consists of a shrouded impeller, a vaneless diffuser, a U-bend and an adjoining vaned return channel. Large channel heights due to high flow rates induce the formation of highly three-dimensional flow phenomena and thus enlarge the losses due to secondary flows. An accurate prediction of this loss behavior by means of numerical investigations is challenging. The published experimental data offer the opportunity to validate the used numerical methods at discrete measurement planes, which strengthens confidence in the numerical predictions. CFD simulations of the stage are initially validated with global performance data and extensive static pressure measurements in the vaneless diffuser. The comparison of the pressure rise and an estimation of the loss behavior inside the vaneless diffuser provide the basis for a numerical investigation of the flow phenomena in the U-bend and the vaned return channel. The flow acceleration in the U-bend is further assessed via the measured two-dimensional pressure field on the hub wall. The upstream potential field of the return channel vanes allows an evaluation of the resulting flow angle. Measurements within the return channel provide information about the deceleration and turning of the flow. In combination with the numerical simulations, loss mechanisms can be identified and are presented in detail in this paper.

Development and Characterization of Al-Si-Cu FGM Using Centrifuge Technique

In this work Al-Si-Cu Functionally Graded Material (FGM) is developed using centrifuge technique. The method used in this work to produce FGM is totally different compared to other centrifugal process which helped in producing solid cylindrical parts. The FGM is characterized through Microstructure and Hardness and it is found that the Cu segregated at the bottom of the casting and Si at the top due to the density difference. Similarly the hardness and the ultimate tensile strength at the bottom of the casting and at the top of the casting region is more when compared to region in-between the top and bottom of the casting.

Evaluation of Wearing Properties of Polyamide 66 Containing Glass Wool

Glass wool is discontinuous glass fiber with the average diameters of 3-4 μm produced by means of centrifugal process, and mainly applied to heat and acoustic insulation. But, there are few reports on glass wool applied to reinforcement of plastic materials in which chopped strand made by chopping continuous glass fiber is used primarily. In this study, the polyamide 66-based composite material samples containing glass wool were prepared and its wear property as a mechanical property was evaluated. It was found that the composite has an advantage on the wear property compared with a conventional glass fiber reinforced plastic, and the result suggests that glass wool has a possibility as a reinforcement material applied to plastic parts required wear resistance.

Anti-Corrosion Performance of Four Hot Dip Galvanizing Bolts

The hot-dip galvanizing coating can promote the anti-corrosion performance of the bolts in outdoor steel structure engineering. But the anti-corrosion performance cannot match that of the steel due to the centrifugal process. In this paper, the anti-corrosion performance of four kinds of bolts obtained from different company was researched by the neutral salt spray test method. The results show that the anti-corrosion performance of the all four bolts was unsatisfactory. The reasons were studied through testing the thickness of the coating, coating uniformity, surface morphology and elemental composition. The results show that the causes are the lower thickness of the hot-dip coatings, too much defects on the surface of the coatings and the elemental composition impurity.

Study on Mass Segregation Phenomenon of Al2O3 Ceramic Slurries during Centrifugal Slip Casting

Mass segregation of Al2O3 slurries during centrifugal slip casing has important effect on microstructure and mechanical property of sintered Al2O3 ceramic, so the study on effect of centrifugal process parameters on mass segregation of slurries has significant meaning. Al2O3 ceramic slurries with different solid content varying from 30vol% to 50vol% were prepared. The effect of centrifugal time, centrifugal acceleration and solid content of slurries on green density uniformity of Al2O3 ceramic compacts was studied. The microstructure of centrifuged compacts was observed using scanning electron microscopy (SSX-505). The results show with the increase of centrifugal acceleration and solid content of slurries, the mass segregation of Al2O3 particles with different size increases and decreases, respectively. However, centrifugal time has no obvious effect on green density uniformity. SEM observation shows the green compacts have uniform microstructure when centrifuged at 2860g for 2h with 50vol% slurries.