INTRODUCTION

REFERENSI 1.C.J. GEANKOPLIS : “TRANSPORT PROCESSES AND UNIT OPERATIONS”, EDISI 3, PRENTICE HALL INTERNATIONAL, N. de NEVERS : “FLUID MECHANICS FOR CHEMICAL ENGINEERS”, EDISI 2, McGRAW HILL INTERNATIONAL, R.S. BRODKEY & H.C. HERSHEY: “TRANSPORT PHENOMENA, A UNIFIED APPROACH”, INTERNATIONAL EDITION, McGRAW HILL, J.M. WELTY, C.E. WICKS & R.E. WILSON: “FUNDAMENTAL OF MOMENTUM, HEAT, AND MASS TRANSFER”, EDISI 4, JOHN WILEY & SONS, 2001

MOMENTUM TRANSFER or FLUID MECHANICS

Sir Isaac Newton

MECHANICS AND GRAVITATION MECHANICS AND GRAVITATION According to the well-known story, it was on seeing an apple fall in his orchard at some time during 1665 or 1666 that Newton conceived that the same force governed the motion of the Moon and the apple. He calculated the force needed to hold the Moon in its orbit, as compared with the force pulling an object to the ground. He also calculated the centripetal force needed to hold a stone in a sling, and the relation between the length of a pendulum and the time of its swing. These early explorations were not soon exploited by Newton, though he studied astronomy and the problems of planetary motion. Correspondence with Hooke ( ) redirected Newton to the problem of the path of a body subjected to a centrally directed force that varies as the inverse square of the distance; he determined it to be an ellipse, so informing Edmond Halley in August Halley's interest led Newton to demonstrate the relationship afresh, to compose a brief tract on mechanics, and finally to write the Principia. Book I Book I of the Principia states the foundations of the science of mechanics, developing upon them the mathematics of orbital motion round centres of force. Newton identified gravitation as the fundamental force controlling the motions of the celestial bodies. He never found its cause. To contemporaries who found the idea of attractions across empty space unintelligible, he conceded that they might prove to be caused by the impacts of unseen particles. Book II Book II inaugurates the theory of fluids: Newton solves problems of fluids in movement and of motion through fluids. From the density of air he calculated the speed of sound waves. Book III Book III shows the law of gravitation at work in the universe: Newton demonstrates it from the revolutions of the six known planets, including the Earth, and their satellites. However, he could never quite perfect the difficult theory of the Moon's motion. Comets were shown to obey the same law; in later editions, Newton added conjectures on the possibility of their return. He calculated the relative masses of heavenly bodies from their gravitational forces, and the oblateness of Earth and Jupiter, already observed. He explained tidal ebb and flow and the precession of the equinoxes from the forces exerted by the Sun and Moon. All this was done by exact computation. Newton's work in mechanics was accepted at once in Britain, and universally after half a century. Since then it has been ranked among humanity's greatest achievements in abstract thought. It was extended and perfected by others, notably Pierre Simon de Laplace, without changing its basis and it survived into the late 19th century before it began to show signs of failing. See Quantum Theory; Relativity.

TRANSPORT PHENOMENA ? TRANSPORT PHENOMENA = FENOMENA PERPINDAHAN = PERISTIWA PERPINDAHAN TRANSPORT PHENOMENA MELIBATKAN 3 (TIGA) PROSES PERPINDAHAN : PERPINDAHAN MASSA PERPINDAHAN PANAS PERPINDAHAN MOMENTUM PROSES PERPINDAHANNYA SERING TERJADI SECARA SIMULTAN DENGAN ANALOGI SAMA

MEKANISME TRANSFER MEKANISME TRANSFER MOLEKULER (MTM) MEKANISME TRANSFER TURBULENSI (MTB)

MEKANISME TRANSFER PANAS MOLEKULER HEAT FLOW HEAT TRANSFER FIRE BENTUK ANALOGI HK FOURIER Fluks panas J/s.m 2 Difusivitas panas, m 2 /s Kons. panas J/m 3

MEKANISME TRANSFER MASSA MOLEKULER N2O2 MASS TRANSFER HUKUM FICK BENTUK ANALOGI Fluks massa A mol/s.m 2 Difusivitas molekul A dlm B, m 2 /s Kons. massa A mol/m 3

MEKANISME TRANSFER MOMENTUM MOLEKULER MOMENTUM TRANSFER LAMINAR FLOW HK NEWTON VISKOSITAS BENTUK ANALOGI Fluks mom arah z akibat komponen kecepatan x (kg.m/s)/s.m 2 Difusivitas momentum,   /  m 2 /s Arah perpindahan momentum x z

MOMENTUM TRANSFER ? MOMENTUM TRANSFER = FLUID MECHANICS MOMENTUM TRANSFER : THE STUDY OF FORCE AND MOTION OF FLUIDS

PENTINGNYA MEKANIKA FLUIDA ? (1) PROCESS INDUSTRIES:.PROCESS INDUSTRIES: BEBERAPA MATERIAL ADALAH DALAM BENTUK FLUIDA DAN HARUS DISIMPAN, DIHANDLING, DIPOMPA. HYDRAULICS:HYDRAULICS: PIPE FLOW, PUMPS, TURBINES PARTICLE DYNAMICS :PARTICLE DYNAMICS : FLOW AROUND PARTICLE, INTERACTION OF PARTICLES AND FLUIDS (SETTLING, SLURRIES, PNEUMATIC TRANSPORT, FLUIDIZED BED, AIR POLLUTANT PARTICLE) MULTIPHASE FLOW:MULTIPHASE FLOW: COMBUSTION, SPRAYS, FLOW IN REACTOR, DISTILATION COULOMN

PENTINGNYA MEKANIKA FLUIDA? (2) METEREOLOGY:METEREOLOGY: FLOW OF THE ATMOSPHERE HYDROLOGY:HYDROLOGY: FLOW WATER IN THE GROUND VISCOUS FLOWS :VISCOUS FLOWS : LUBRICATION, INJECTION MOLDING, EKSTRUKSI POLIMER, DLL

IDE DASAR dalam MEKANIKA FLUIDA (1) 4 PRINCIPLES:4 PRINCIPLES: CONSERVATION OF MASS CONSERVATION OF ENERGY= FIRST LAW OF THERMO SECOND NEWTON’S LAW=SECOND LAW THERMO NEWTON’S LAW OF MOTION SIMPLE FLOWS :SIMPLE FLOWS : BILA 4 PRINSIP DASAR TERSEBUT DAN SIFAT FISIK TERUKUR DAPAT DISELESAIKAN LANGSUNG SECARA MATEMATIKA  GAYA, KECEPATAN, DLL COMPLEK FLOWS :COMPLEK FLOWS : BILA 4 PRINSIP TERSEBUT HANYA DAPAT DISELESAIKAN DENGAN EKSPERIMEN, ANALISIS DIMENSI & SIMULASI CFD

EXAMPLE OF COMPLEX FLOWS ARROUND A SUBMERGED OBJECT

EXAMPLE OF COMPLEX FLOWS IN STIRRED TANK ANALYZED BY CFD

Fluid velocity vector

Solid concentration contour C av = 5% C av = 20%

Local gas hold up at several position from baffle

EXAMPLE OF COMPLEX FLOWS IN COMBUSTION ANALYZED BY CFD

Vektor Kecepatan dalam Ruang Bakar

Distribusi Suhu dalam Ruang Bakar

Distribusi CO 2 dalam Ruang Bakar (a)

Distribusi O 2 dalam Ruang Bakar