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Abstrak :
Saat ini, kualitas udara ruangan menjadi salah satu ancaman kesehatan bagi masyarakat modern. Penelitian oleh Kleipes et.al, 2001 menujukan bahwa manusia modern menghabiskan hampir 90% waktunya dalam ruangan. Kualitas udara ruang dipengaruhi oleh berbagai macam polutan yang terdiri dari CO2, CO, VOC, Radon dan partikulat. . Thermal Precipitator adalah salah satu alat yang dapat gunakan untuk membersihkan udara dan bekerja berdasarkan prinsip thermophoresis, yaitu gaya yang bekerja akibat adanya gradien temperatur. Untuk memahami karakteristik efek thermophoresis pada suatu thermal precipitator dengan ukuran partikel dan temperatur yang divariasikan, dilakukan suatu simulasi berdasarkan prinsip computational fluid dynamics, perpindahan kalor dan particle tracing. Variasi beda temperatur yang dilakukan adalah sebesar 30, 40, 50, 60, 70, 80 dengan ukuran partikel 0.05, 0.1, 0.25, 0.5, 0.75, 1,1.5, 2 dan 2.5 µm Simulasi tersebut dilakukan pada perangkat lunak COMSOL Multiphysics 5.4. Hasil yang didapat berbentuk distribusi partikel, jarak tempuh partikel dan kebutuhan energi precipitator. Terdapat perbedaan yang besar yang diakibatkan perbedaan posisi plat panas dan dingin. Selain itu, pada rentang partikel 0.05-0.25 µm, thermophoresis menjadi driving force pergerakan partikel. Sedangkan efisiensi pada seluruh ukuran partikel sebesar 100% didapat pada beda temperatur diatas 50K untuk plat panas diletakan pada bagian atas dan 70K pada kasus plat panas diletakan pada bagian bawah. Sehingga, thermal precipitator berpotensi untuk menangkap partikel – partikel berukuran kecil untuk meningkatkan kualitas udara ruang. Kebutuhan energi precipitator adalah sebesar 150506.70 J/ m3 untuk beda temperatur 80 K dan 53044 J/m3 untuk beda temperatur 30 K. = Indoor air quality has been raised as one of the most pressing health issues facing the urban society. According to Klepeis et.al, 2001 Modern human spends nearly 90% of their time in enclosed spaces or in commuting spaces. IAQ(Indoor Air Quality) is affected by various factors with pollutants ranging from CO2, CO, Radon and particulate matter. One of the available technologies in air cleaning is thermal precipitators that works by utilizing thermophoresis effect. Thermophoresis effects is a force due a temperature gradient existing around a particle. To understand the characteristic and feasibility of the aforementioned technology for indoor air cleaning, a simulation based on the principle of computational fluid dynamics, heat transfer and particle tracing was done on COMSOL 5.4 Software. The parameters concerning the thermal precipitators were varied with temperature difference of 30, 40, 50, 60, 70, 80 K with particle diameter of 0.05, 0.1, 0.25, 0.5, 0.75, 1,1.5, 2 dan 2.5 µm. The simulation results in data regarding particle displacement, particle deposition count and heat transfer. A large difference in precipitator performance was observed, due to heated plate position. Furthermore, Thermophoresis was observed as the driving force for particles ranging between 0.05 to 0.25 µm in size. An efficiency number of 100% across all particle sizes was achieved with a temperature difference of 50 K with the heated plate place above the colder plate while a temperature difference of 70K was required in order to achieve same effect when the heated plate is below the colder plate. Due to the high precipitation efficiency, themal precipitator possesses a high potential to collect fine particulate matter in order to improve indoor air quality. In addition, energy consumption was simulated, peaking at 150506 J/m3 of air cleaned with a temperature difference of 80K and 50344 J/m3 with a temperature difference of 30K

Abstrak :
In this paper, the problem of natural convective heat transfer of kerosene-cobalt nanofluid inside a quarter circular enclosure in the presence of oriented magnetic field has been studied numerically using two-component non-homogeneous model. The round wall of the enclosure is maintained at constant low temperature; the left vertical wall is adiabatic whereas the bottom wall is considered as heated uniformly and non-uniformly. The effects of Brownian motion and thermophoresis are incorporated into the nanofluid model. The Galerkin weighted residual finite element method has been employed to solve the governing partial differential equations after converting them into a non-dimensional form using a suitable transformation of variables. Comparison with previously published work is performed and excellent agreement is obtained. The effects of various model parameters such as Hartmann number, Rayleigh number and magnetic field inclination angle on the streamlines, isotherms and isoconcentrations have been displayed graphically for both uniformly as well as non-uniformly heated bottom wall. In addition, the heat transfer augmentation for various model parameters as well as various thermal boundary conditions have been done in light of the average Nusselt number from the bottom heated wall. The obtained numerical results show that the average Nusselt number is an increasing function of the Rayleigh number, while it is a decreasing function of the Hartmann number.