The paper presents a comparison between two sets of experimental results in a centrifugal flow pump. The tested impeller is the so-called SHF impeller for which many experimental data have been continuously produced to built databases for CFD code validations with various levels of approximation. Measurements have been performed using optical techniques: 2D particle image velocimetry (PIV) technique on an air test model and 2D laser doppler velocimetry (LDV) technique on a water model, both for different flow rates. For the present study, results obtained by these optical techniques are compared together in terms of phase averaged velocity and velocity fluctuations inside the impeller flow passage for design flow rate.
The unsteadiness of the flow at the leading edge of a vaned diffuser represents a source of low efficiency and instability in a centrifugal pump. Furthermore, the internal flow of the impeller can be affected by asymmetric downstream conditions, which results in extra flow unsteadiness and instabilities. The improvement of machine performances can only be achieved if there is a progress in the comprehension of the nature of the complex flow that develops at the gap between the rotor and the stator.This paper presents the results of LDA investigation of the internal flow of a centrifugal pump equipped with a backswept impeller and a vaned diffuser. The data taken in phase with the impeller rotation are presented as animated frames reconstituting a temporal evolution of the flow in radial planes at the diffuser inlet.
The radiation and convection section of a steam cracker are thermally coupled. Optimization and design requires a coupled simulation of both sections. In this work a 1D model for the convection section, CONVEC-1D, is developed. Several models for the different heat transfer phenomena are implemented and evaluated. For flow boiling, an empirical and a mechanistic model are developed and compared for both single-and multicomponent hydrocarbon feeds. The latter is performing best over a wide range of operating conditions, taking into account the different two-phase flow regimes. The coupled iterative procedure is demonstrated for an n-pentane steam cracker convection section.
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