ME211 Ch1
ME211 Ch1
ME211 Ch1
(1) Thermodynamics: The study of energy use and transformation from one form to
another and the physical properties of substances (solids, liquids, gases) involved in
energy use or transformation
(2) Heat transfer: The study of energy flow that is caused by a temperature difference or
phase change
(3) Fluid Mechanics: The study of fluids (liquids, gases) at rest or motion and the
interaction between a solid and a fluid either flowing past or acting on the solid in
some manner.
Thermo–fluid ≡ thermodynamics + heat transfer + fluid mechanics
~1990 2018
• Thermodynamics is the unifying idea for the solution of thermal-fluids system problems
• Governing equations of the thermodynamics are:
conservation of mass
conservation of energy
second law of thermodynamics
Work: performed by a system is the energy transferred to another system that is measured
by the external generalized mechanical constraints on the system. As such, thermodynamic
work is a generalization of the concept of mechanical work in mechanics. Thermodynamic
work encompasses mechanical work plus many other types of work, such as electrical or
chemical. Later we’ill see the classification
Compression and expansion work, electrical work, shaft Work
An electric power plant has an impressive assembly of pumps, turbines, HXs, pipes,
valves, control etc.
Question: How would we start an analysis of such a complex installation?
Answer: Engineer must translate the real picture into something that can be used
in an analysis.
An electric power plant has an impressive assembly of pumps, turbines, HXs, pipes,
valves, control etc.
Question: How would we start an analysis of such a complex installation?
Answer: Engineer must translate the real picture into something that can be used
in an analysis.
Many problems are too difficult to solve with their real complexity. An assumption
or assumptions is/are used to simplify the problem
• enough appropriate assumptions to render the problem solvable
• BUT, not so many as to invalidate the result because simplified system is too
far from the actual situation
• CFD is a branch of fluid mechanics which utilize numerical methods and algorithms to
analyze fluid flow problems.
• CFD requires to solution of nonlinear, partial differential equations (PDEs) which
governs to fluid flow and heat transfer characteristics of the fluids (liquids and gases).
The interaction of the fluid with the surfaces defined by boundary conditions.
• With high-speed supercomputers, better solutions can be achieved.
• Experimental validation of the computer results is performed using an experimental
set-up mainly the wind tunnels.
• Some methods to attach the numerical solution of PDEs: Finite Difference Method,
Finite Element Method (FEM), Finite Volume Method (FVM), Spectral Element
Method, Boundary Element Method, Lattice Boltzmann Method etc.
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Microfluidics is a way to
address these problems:
Reagent 1 Reagent 2
Carrier Fluid