Impeller-Diffuser Interaction in Centrifugal Compressors: Numerical Analysis of the Radiver Test Case

Water-mist systems have become a promising technology in the fire-fighting field over the last twenty years. The present work is aimed at employing the available knowledge on water-mist sprays in an experimental and numerical analysis of the suppression mechanism. Therefore, a water-mist system has been operated within a typical fire case. Most notably, this latter is constituted by a heptane pool fire: experiments have been carried out inside a test chamber, where a set of thermocouples has conveniently been placed to evaluate the thermal transient at different locations of interest. Some free-combustion tests have been run as a benchmark to validate combustion models. Then, a typical water-mist nozzle has been inserted and activated to realize control, suppression and potential extinction of the generated fire. The recognized FDS (Fire Dynamics Simulator) and Fluent® codes have been challenged in reproducing the test case: thermal transient and suppression time have been considered as parameters for validation. Therefore, the water-mist spray has been modeled and the already mentioned results about its characterization have been implemented as initial or boundary conditions. Moreover, the fire scenario has been modeled as well. A good agreement between experimental and numerical results has been obtained, even under some approximations, with specific reference to combustion mechanisms.

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Design and Optimization of Multi-Stage Centrifugal Compressors With Uncertainty Quantification of Off Design Performance

Volume 2C: Turbomachinery ◽

10.1115/gt2017-63770 ◽

2017 ◽

Author(s):

A. Romei ◽

R. Maffulli ◽

C. Garcia Sanchez ◽

S. Lavagnoli

Keyword(s):

Uncertainty Quantification ◽

Oil And Gas ◽

Low Cost ◽

Design Procedure ◽

Design Tool ◽

Test Case ◽

Centrifugal Compressors ◽

Design Performance ◽

Leading Role ◽

Multi Stage

The use of multi-stage centrifugal compressors carries out a leading role in oil and gas process applications. Green operation and market competitiveness require the use of low-cost reliable compression units with high efficiencies and wide operating range. A methodology is presented for the design optimization of multi-stage centrifugal compressors with prediction of the compressor map and estimation of the uncertainty limits. A one-dimensional (1D) design tool has been developed that automatically generates a multi-stage radial compressor satisfying the target machine requirements based on a few input parameters. The compressor performance map is then assessed using the method proposed by Casey-Robinson [1], and the approach developed by Al-Busaidi-Pilidis [2]. The off-design performance method relies on empirical correlations calibrated on the performance maps of many single-stage centrifugal compressors. An uncertainty quantification study on the predicted performance maps was conducted using Monte Carlo method (MCM) and generalized Polynomial Chaos Expansion (gPCE). Finally, the design procedure has been coupled to an in-house optimizer based on evolutionary algorithms. The complete design procedure has been applied to a multi-stage industrial compressor test case. A multi-objective optimization of a multi-stage industrial compressor has been performed targeting maximum compressor efficiency and flow range. The results of the optimization show the existence of optimum compressor architectures and how the Pareto fronts evolve depending on the number of stages and shafts.

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Thermal Analysis of Stacked Ni-MH Battery

10.1115/imece1999-1001 ◽

1999 ◽

Author(s):

Katsumi Hisano ◽

Hideo Iwasaki ◽

Masaru Ishizuka ◽

Tetsuya Yamane

Keyword(s):

Thermal Analysis ◽

Numerical Analysis ◽

Temperature Rise ◽

Test Case ◽

Charge Retention ◽

Calculated Temperature ◽

Computational Load ◽

Three Stages ◽

Mh Battery ◽

Good Agreement

Abstract Numerical analysis was carried out to evaluate the temperature rise and charge retention of Ni-MH batteries as pallet loads. In this paper, thermal analysis of pallet loads which contain 2400 mAh Ni-MH batteries is considered as a test case. To reduce computational load, thermal analysis was performed in three stages. Measured and calculated temperature rise of the load showed good agreement, and it can be observed that there exists an appropriate charge retention of the battery to sustain high retention during transportation.

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Effect of Rotor–Stator Interaction on Impeller Performance in Centrifugal Compressors

International Journal of Rotating Machinery ◽

10.1155/s1023621x99000123 ◽

1999 ◽

Vol 5 (2) ◽

pp. 135-146 ◽

Cited By ~ 1

Author(s):

K. Sato ◽

L. He

Keyword(s):

Navier Stokes ◽

Test Case ◽

Steady Flows ◽

Centrifugal Compressors ◽

Vaned Diffuser ◽

Rotor Stator Interaction ◽

Flow Through ◽

And Performance ◽

Unsteady Effects ◽

Blade Row Interaction

A 3-D unsteady thin-layer Navier-Stokes code has been used to calculate the flow through a centrifugal compressor stage. The validation of the code for steady flows in centrifugal compressors was conducted for the Krain’s impeller with a vaneless diffuser as a test case and the numerical results were compared with the experimental results. The predicted flow field and performance agreed well with the experimental data. An unsteady stage solution was then conducted with this impeller followed by a generic low-solidity vaned-diffuser to examine the unsteady effects on the impeller performance. The computational results showed a stabilising effect of the blade row interaction.

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The influence of distance between vehicles in platoon on aerodynamic parameters

EPJ Web of Conferences ◽

10.1051/epjconf/201818002030 ◽

2018 ◽

Vol 180 ◽

pp. 02030

Author(s):

Renata Gnatowska ◽

Marcin Sosnowski

Keyword(s):

Numerical Analysis ◽

Wind Tunnel ◽

Velocity Fields ◽

Simplified Model ◽

Test Case ◽

Safety Issues ◽

Traffic Conditions ◽

Optimal Distance ◽

Aerodynamic Parameters ◽

Numerical Research

The paper presents the results of experimental and numerical research focused on the reduction of fuel consumption of vehicles driving one after another in a so-called platoon arrangement. The aerodynamic parameters and safety issues were analyzed in order to determine the optimal distance between the vehicles in traffic conditions. The experimental research delivered the results concerning the drag and was performed for simplified model of two vehicles positioned in wind tunnel equipped with aerodynamic balance. The additional numerical analysis allowed investigating the pressure and velocity fields as well as other aerodynamics parameters of the test case.

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