Variational method in the design of an optimum solar water heater storage tank

Solar water heaters are now have been accepted as a reliable source of providing hot water heating in many domestic homes and are becoming more popular. Unfortunately, solar water heaters are still considered luxurious hardware in Malaysia. A cheaper and efficient solar water heater system is required to be designed. The only way to produce cheaper and efficient product is through the optimization process to obtain the minimum cost but still maintain the specification required or known as constraints. In this paper, the vertical water storage tank will be analyzed to obtain the optimum cost. Thermosyphon-flow solar water heating system is preferred for obvious economic reasons since they do not require circulation pumps and control units. Average temperature of the hot water in the storage tank is determined through temperature distribution simulation. The overall average temperature obtained is 49.3ºC and is used to solve the optimization problem. The constraints in the optimization process are the tank volume and heat losses from the water in the tank. The Lagrange multiplier method, which is based on the differentiation of the objective function and the constraints is applied. The minimum cost obtained for storage tank volume of 225 litres is RM 1321.6

Dinamik aliran: pengenalan dan teori

Buku ini mengandungi beberapa bab iaitu kandungan: prakata, bab 1 konsep–konsep aliran bendalir, konsep sistem dan isipadu kawalan, fluk vektor, penerbitan teorem angkut reynolds, bab 2 persamaan keselanjaran dan penggunaannya, hukum keabadian jisim, hal-hal khusus persamaan keselanjaran, persamaan keselanjaran dalam bentuk pembeza, bab 3 persamaan momentum dan penggunaannya, penerbitan hukum keabadian momentum aliran, daya tekanan bersih, fluk momentum matra–satu, bab 4 persamaan tenaga dan penggunaannya, penerbitan hukum keabadian tenaga aliran, unsur–unsur ws, penyederhanaan persamaan tenaga, kesusutan turus, bab 5 prinsip aliran likat, persamaan navier–stokes, beberapa penyelesaian eksak persamaan navier–stokes, aliran couette, bab 6 aliran lapisan sempadan lamina, anggapan lapisan sempadan, konsep tebal lapisan anjakan dan momentum, penyelesaian blasius, bab 7 prinsip aliran unggul, pembahasan tentang persamaan euler, pengamiran persamaan euler, aliran berputar dan tidak berputar, edaran, bab 8 aliran upaya bendalir tidak boleh mampat, konsep rangkap arus aliran matra satu, hubungan di antara rangkap arus dan halaju upaya, aliran sederhana bermatra–satu, kaedah superposisi aliran sederhana, bab 9 prinsip matra–satu aliran gas unggul, konsep awal, persamaan menakluk aliran gas, penerbitan laju gelombang suara, hubungan proses aliran isentropik, bab 10 aliran quasi matra–satu gas unggul, persamaan menakluk masalah, hubungan di antara luas dan halaju, aliran isentropik dalam saluran menumpu–capah, bibliografi serta indeks

Hidraul : suatu penyelesaian

Buku ini mengandungi beberapa bab iaitu kandungan: prakata, catatan sejarah, bab 1 ciri fizik bendalir, pendahuluan, takrifan, unit, bab 2 statik bendalir, perubahan keamatan tekanan, pengukuran tekanan, daya pada satah dan permukaan melengkung, ketimbulan, bab 3 hukum aliran bendalir, pengelasan jenis aliran, bab 4 penggunaan hukum aliran bendalir, garis tenaga dan garis gred hidraul, meter venturi, tiub pitot, bab 5 analisis bermatra, pengenalan, kaedah rayleigh, kaedah buckingham–p, bab 6 aliran dalam paip, persamaan darcy dan chezy, aliran lamina dalam paip, pengenalan kepada aliran lapisan sempadan dan gelora, bab 7 aliran seragam di saluran, seksyen ekonomis, tenaga tentu, aliran melewati suatu bonjolan di dasar, bab 8 aliran berubah bertahap di saluran, analisis aliran berubah bertahap, pengelasan lengkung air balik, analisis susuk dan titik kawalan, bab 9 model hidraul permukaan terbuka, hukum pengawalan model, penentuan skala model apabila kesasaran diambil kira, penentuan skala apabila pencetekan diambil kira, bab 10 aliran unggul boleh mampatpersamaan tenaga, halaju bunyi, tekanan dan suhu genangan, bab 11 aliran unggul dan nyata, mekanik pemisahan aliran, geseran dan hela seretan, edaran dan lif, bab 12 paluan air, penutupan injap seketika, penentuan tekanan lebih serta penutupan injap cepat dan perlahan

Simulation Studies of Gas-Solid in the Riser of a Circulating Fluidized Bed

A numerical parametric study was performed on the influence of various riser exit geometries on the hydrodynamics of gas-solid two-phase flow in the riser of a Circulating Fluidized Bed (CFB). A Eulerian continuum formulation was applied to both phases. A two fluid framework has been used to simulate fully developed gas-solid flows in vertical riser. A two dimensional Computational Fluid Dynamics (CFD) model of gas-particle flow in the CFB has been investigated using the code FLUENT. The turbulence was modeled by a k-e turbulence model in the gas phase. The simulations were done using the geometrical configuration of a CFB test rig at the Universiti Teknologi Malaysia (UTM). The CFB riser column has 265 mm (width), 72 mm (depth) and 2.7 m height. The riser is made up of interchangeable Plexiglas columns. The computational model was used to simulate the riser over a wide range of operating and design parameters. In addition, several numerical experiments were carried out to understand the influence of riser end effects, particle size, gas solid velocity and solid volume fraction on the simulated flow characteristics. The CFD model with a k-e turbulence model for the gas phase and a fixed particle viscosity in the solids phase showed good mixing behaviour. These results were found to be useful in further development of modeling of gas solid flow in the riser

An improved scheme for parabolic flow along a curved rectangular duct

The use of parabolized Navier-Stokes (PNS) equations to model internal flow problems has been gaining momentum. The main advantage of using PNS equations to simulate incompressible viscous flows is the suppression of elliptical behavior in the streamwise direction of the flow wherein the governing equations become parabolic in this direction. Thus, these equations are solvable by space-marching techniques, saving considerable storage and computational time. Patankar and Spalding (1972), Briley (1974), Garg (1985), Pouagare and Lakshminarayana (1986) and Govindan and Lakshminarayana (1988) have developed their own scheme to solve the PNS equations for developing flow in straight ducts. Their computations reveal a remarkable agreement with the available experimental data of Sparrow et al. (1967) and Goldstein and Kreid (1967). The potential of PNS equations in predicting laminar flow in a curved circular pipe was tapped by Patankar et al. (1974) using the scheme of Patankar and Spalding (1972). Their predictions show a very satisfactory agreement with the available experimental data of Mori and Nakayama (1965) and Austin (1971) and the theoretical solution of Akiyama and Cheng (1971). Thereafter, a number of investigators has followed the works of Patankar et al. (1974) and even extended the use of PNS equations to developing flow in curved rectangular ducts

Streamlike function formulation of entry flow

A numerical study of fluid flow in a rectangular duct is presented. The flow of the working fluid is assumed to be steady and laminar. It is also assumed that the flow field is rotational. The flow analysis is carried out in three dimensional space using Cartesian coordinate. The problem formulation results in a non-linear type partial differential equation for the through flow velocity, which is solved numerically using marching technique. The other formulation is an elliptic type partial differential equation, for which the streamlike function is solved using successive over relaxation method. The results obtained are investigated to determine the velocity distribution across a constant duct cross section and the development of through flow velocity in the duct

Mekanik bendalir gunaan

Buku ini mengandungi beberapa bab iaitu kandungan, prakata, bab 1 tekanan bendalir pada permukaan, permukaan satah, permukaan melengkung, bab 2 jasad terapung, keapungan, ayunan melintang suatu jasad terapung, bab 3 gerak translasi dan putaran jasad bendalir, perubahan tekanan disebabkan oleh daya berat dan cepat, gerakan mengufuk linear, bab 4 kinematik gerakan bendalir, kaedah penerangan, medan aliran, bab 5 kinematik aliran, medan aliran, medan aliran nirputaran, bab 6 hukum keabadian jisim, persamaan keselanjaran dalam bentuk kamiran, persamaan keselanjaran dalam bentuk pembeza, bab 7 hukum keabadian momentum, persamaan momentum dalam bentuk kamiran, persamaan momentum dalam bentuk pembeza, bab 8 persamaan bernoulli, persamaan euler, kamiran persamaan euler, bab 9 hukum momentum, persamaan momen momentum, bab 10 hukum keabadian tenaga, persamaan tenaga yang am, persamaan tenaga aliran mantap, bibliografi, indeks

Analisis dimensi & similitud dalam mekanik bendalir

Analisis dimensi dan similitud merupakan satu cabang ilmu yang menyelami fenomena alam. Memang banyak kejadian alam yang tidak mampu dirumuskan secara matematik. Ini kerana kejadian berkenaan amat kompleks. Sebagai contoh, perhatikan buih yang berada di atas permukaan air. Pertama, apabila air melanggar batu, maka terjadilah buih. Kemudian buihpun dialirkan pergi meninggalkan batu. Ketika mengalir tadi buih menyurih satu lintasan. Apakah mungkin dapat ditentukan bentuk surihan lintasan buih air itu? Ada ketika buih diam dan pada masa yang lain buih seakan–akan dialirkan Bolehkah ditentukan daya yang bertindak pada buih ini? Jawapannya boleh! Kaedahnya adalah dengan analisis dimensi. Buku ini sesuai sebagai rujukan dan panduan para pelajar kejuruteraan, terutamanya Kejuruteraan Mekanikal, Awam, dan Kimia di Institusi Pengajian Tinggi serta sebagai bahan bacaan umum kepada mereka yang berminat untuk mengetahui dan memahami tentang fenomena alam

Statik benda alir

Buku ini mengandungi beberapa bab iaitu kandungan, prakata, bab 1 pengenalan kepada statik benda alir, di antara statik dan dinamik benda alir, apa itu benda alir, sifat fizik benda alir, bab 2 sifat sederhana suatu benda alir, kelikatan, tegangan permukaan, kererambutan, bab 3 agihan tekanan daya benda alir, hukum pascal, statik suatu sistem benda alir, persamaan hidrostatik, tekanan dan turu, bab 4 statik benda alir, daya hidrostatik, daya hidrostatik pada suatu permukaan rata, daya hidrostatik pada suatu permukaan melengkung, bab 5 keapungan jasad dalam benda alir statik, hukum keapungan archimedes, kestabilan jasad terapung, bab 6 keseimbangan relatif sejasad benda alir, agihan tekanan benda alir yang mengalami cepatan, benda alir yang berputar seakan suatu jasad tegar, bibliografi, lampiran, indeks

Analisis aliran momentum

Buku ini mengandungi beberapa bab iaitu kandungan: mukadimah, kata penghantar, bab 1 pengenalan kepada hukum asas aliran, aliran mantap dan tak mantap, sistem dan isipadu kawalan, bab 2 analisis medan aliran tak berputar, aspeks matematik medan aliran berputar, medan vortisiti dan edaran, bab 3 analisis aliran likat, pentingnya nombor reynolds, persamaan menakluk medan aliran likat, bab 4 analisis aliran boleh mampat dimensi-satu, pengelasan aliran boleh mampat, persamaan menakluk dan beberapa aspeks matematik, bahan bacaan tambahan, contoh penyelesaian latihan, latihan tambahan serta indeks