ANALISIS PENGARUH LEBAR CELAH DAN JARAK ANTAR MAGNET TERHADAP DAYA DAN JARAK TEMPUH KAPAL PADA MHD CHANNEL TIPE HALL

Magnetohidrodinamika yang memanfaatkan medan magnetik serta cairan atau fluida yang mana untuk merubah menjadi energi gerak merupakan salah satu upaya pengganti penggerak kapal dari sistem penggerak propeler. Fokus dari penelitian ini yaitu untuk mengetahui pengaruh lebar celah channel terhadap daya dan kecepatan kapal pada channel type hall connection dengan sistem perubahan lebar celah channel, dari perubahan lebar celah channel tersebut akan meneliti pengaruh perubahan lebar celah channel dan jarak antar magnet terhadap kecepatan dan daya dorong prototype kapal MHD serta mencari nilai efisiensi daya dorong yang dikeluarkan dari keempat channel percobaan yang dibuat. Dari penelitian yang telah dilakukan ini dapat ditarik kesimpulan bahwa lebar celah dan jarak antar magnet sangat mempengaruhi terhadap daya dorong kapal yang dikeluarkan dan kecepatan jarak tempuh kapal. Sehingga dari empat percobaan tersebut didapatkan ukuran yang paling optimal untuk mendapatkan kecepatan dengan efisiensi daya dorong paling besar yakni saat menggunakan ukuran channel 120mm x 23mm x 25mm dengan menggunakan ukuran magnet 12 mm x 20mm x 10mm.

Symmetric MHD Channel Flow of Nonlocal Fractional Model of BTF Containing Hybrid Nanoparticles

A nonlocal fractional model of Brinkman type fluid (BTF) containing a hybrid nanostructure was examined. The magnetohydrodynamic (MHD) flow of the hybrid nanofluid was studied using the fractional calculus approach. Hybridized silver (Ag) and Titanium dioxide (TiO2) nanoparticles were dissolved in base fluid water (H2O) to form a hybrid nanofluid. The MHD free convection flow of the nanofluid (Ag-TiO2-H2O) was considered in a microchannel (flow with a bounded domain). The BTF model was generalized using a nonlocal Caputo-Fabrizio fractional operator (CFFO) without a singular kernel of order α with effective thermophysical properties. The governing equations of the model were subjected to physical initial and boundary conditions. The exact solutions for the nonlocal fractional model without a singular kernel were developed via the fractional Laplace transform technique. The fractional solutions were reduced to local solutions by limiting α → 1 . To understand the rheological behavior of the fluid, the obtained solutions were numerically computed and plotted on various graphs. Finally, the influence of pertinent parameters was physically studied. It was found that the solutions were general, reliable, realistic and fixable. For the fractional parameter, the velocity and temperature profiles showed a decreasing trend for a constant time. By setting the values of the fractional parameter, excellent agreement between the theoretical and experimental results could be attained.

Comparison of subgrid-scale models for large-eddy simulation of hydrodynamic and magnetohydrodynamic channel flows

Purpose This paper aims to address the performance of different subgrid-scale models (SGS) for hydro- (HD) and magnetohydrodynamic (MHD) channel flows within a collocated finite-volume scheme. Design/methodology/approach First, the SGS energy transfer is analyzed by a priori tests using fully resolved DNS data. Here, the focus lies on the influence of the magnetic field on the SGS energy transport. Second, the authors performed a series of 18 a posteriori model tests, using different grid resolutions and SGS models for HD and MHD channel flows. Findings From the a priori analysis, the authors observe a quantitative reduction of the SGS energy transport because of the action of the magnetic field depending on its orientation. The a posteriori model tests show a clear improvement because of the use of mixed-models within the numerical scheme. Originality/value This study demonstrates the necessity of improved SGS modeling strategies for magnetohydrodynamic channel flows within a collocated finite-volume scheme.