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"This book comprises select proceedings of the International Conference on Future Learning Aspects of Mechanical Engineering (FLAME 2018). The book gives an overview of recent developments in the field of thermal and fluid engineering, and covers theoretical and experimental fluid dynamics, numerical methods in heat transfer and fluid mechanics, different modes of heat transfer, multiphase transport and phase change, fluid machinery, turbo machinery, and fluid power. The book is primarily intended for researchers and professionals working in the field of fluid dynamics and thermal engineering. "

"This Volume 5 of the successful book package "Multiphase flow dynamics" is devoted to nuclear thermal hydraulics which is a substantial part of nuclear reactor safety. It provides knowledge and mathematical tools for adequate description of the process of transferring the fission heat released in materials due to nuclear reactions into its environment. It step by step introduces into the heat release inside the fuel, temperature fields in the fuels, the "simple" boiling flow in a pipe described using ideas of different complexity like equilibrium, non equilibrium, homogeneity, non homogeneity. Then the "simple" three-fluid boiling flow in a pipe is described by gradually involving the mechanisms like entrainment and deposition, dynamic fragmentation, collisions, coalescence, turbulence. All heat transfer mechanisms are introduced gradually discussing their uncertainty. Different techniques are introduced like boundary layer treatments or integral methods. Comparisons with experimental data at each step demonstrate the success of the different ideas and models. After an introduction of the design of the reactor pressure vessels for pressurized and boiling water reactors the accuracy of the modern methods is demonstrated using large number of experimental data sets for steady and transient flows in heated bundles. Starting with single pipe boiling going through boiling in the rod bundles the analysis of complete vessel including the reactor is finally demonstrated. Then a powerful method for nonlinear stability analysis of flow boiling and condensation is introduced. Models are presented and their accuracies are investigated for describing critical multiphase flow at different level of complexity. Therefore the book presents a complete coverage of the modern nuclear thermal hydrodynamics."

"Fraktal adalah penggalan sebuah bentuk geometri yang bisa dibagi lagi menjadi bagian-bagian dimana setiap bagian tersebut akan terlihat mirip dengan bentuk keseluruhannya. Derajat dari batas penggalan suatu fraktal disebut dimensi fraktal. Analisis fraktal ditenggarai cukup efektif untuk memecahkan berbagai permasalahan fenomena alam yang agak rumit. Dalam penelitian ini analisis fraktal diterapkan pada proses fingering aliran celah sempit fluida Newtonian. Analisis fraktal ini dilakukan dengan menghitung dimensi fraktal dari pola aliran yang terbentuk dan mencari korelasinya dengan viskositas fluida, lebar celah dan sudut kemiringan plat kaca, serta gradien temperatur. Dari hasil analisis yang dilakukan, diperoleh beberapa karakteristik pola aliran yang terbentuk. Dimensi fraktal dari pola aliran akan meningkat seiring dengan pertumbuhan gelombang yang terbentuk. Untuk lebar celah dan sudut kemiringan yang berbeda tidak mempengaruhi karakteristik aliran karena nilai dimensi fraktal terhadap waktu spesifik dari pola alirannya tidak menunjukkan perbedaan. Perbedaan viskositas dari fluida mempengaruhi pola aliran, semakin besar viskositas fluida pertumbuhan gelombang akan semakin kecil. Hal ini ditunjukkan oleh nilai dimensi fraktalnya yang juga semakin kecil. Aliran Hele Shaw melalui medan dengan gradien temperatur positif memiliki pertumbuhan gelombang yang lebih cepat dibanding dengan kondisi normal. Demikian pula dengan aliran Hele Shaw yang melalui medan dengan gradien temperatur negatif namun memiliki karakteristik aliran yang berbeda. Nilai dimensi fraktal aliran ini akan menurun saat t/t*>6.

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Fractals are of rough or fragmented geometric shape that can be subdivided in parts, each of which is (at least approximately) a reduced copy of the whole. The degree of fractal boundary fragmentation is called by fractal dimension. Fractal analysis is powerful to solve the complicated natural phenomenon problems. In this experiment, fractal analysis is applied for fingering process of Newtonian fluid thin space flow.

This fractal analysis is processed by counting the fractal dimension of flow pattern and determining the correlation with fluid viscosity, width of gap, degree of angle and the temperature gradient. From the analysis result, there is some flow pattern characteristic founded. The fractal dimension of the flow pattern will increase in a row with the wave growth. The difference of the width of gap and the degree of angle do not affect the flow characteristic because the fractal dimension of the time specific of the flow pattern has a same value.

The difference of the fluid viscosity affect the flow pattern, higher fluid viscosity cause the reduction of wave growth. This is showed by the reduction of the fractal dimension value. Hele Shaw flow through field with a positive temperature gradient has a faster wave growth than at normal condition. But the Hele Shaw flow through field with a negative temperature gradient has a different flow characteristic. Fractal dimension value of this flow will decrease at t/t* > 6."