Thermodynamics and Thermics - 5EUS5TEN

Goal(s)

The module is about energy exchanges and transformations dealing with moving fluid. The question is approached by a global problematic where the stress is put on thermodynamics and transformation process (combustion turbomachines, combustion rotating machines and steam engine, gasification processes) and by a local approach where the thermal exchanges are considered. The objective is to precise the basic concepts that allow a calculation and a sizing of the energy system (aerospace propulsion, energy production) but also identifying the limits of their possible optimization. Lectures provided by industrialists complete the basic teachings (thermal exchangers).

Content(s)

Convective and radiative heat transfer :
Phenomenology, heat transfer modes, thermal resistances and their limits, radiation with or without participating media, natural and forced convection for internal / external flows, laminar or turbulent.
Radiometry / black body: radiometric quantities, radiative equilibrium and black body, Planck law.
Surface radiation: phenomenology, grey/lambertian surfaces, Snell's law, real surfaces, view factors
Participating media: radiative transfer equation, emission / absorption in gases,diffusion (Rayleigh/Mie)
Convection equations, models with turbulent viscosity, incompressible flows, Boussinesq approximation, boundary layer approximations.
Scale analysis, application to those equations, dimensionless numbers and their use in transfer laws
Flat plate boundary layer, scale analysis, profiles (Blasius, log.law), transfer laws
Natural convection on a wall: scale analysis, transfer laws, case of horizontal walls
Forced convection in ducts: mixing temperature, entry length, fully developed flow, developed thermal solution for constant flux or temperature. Profiles and transfer in developed conditions.
Natural convection phenomena in internal flows: thermosyphons, cavities, stratification, instability.

Thermodynamique des machines
The course is mainly focused on the thermodynamics of heat-engines. The first part concerns idealized reversible and irreversible transformations and cycles. A special attention is adressed to the nature of the intrinsec irreversibilites of ideal gas and vapour cycles. Next, for each family of heat engine (gas-turbines, turbojets, internal combustion engines, steam-turbines) a brief overview is developped about the consequences of technological constraints on the effective limits of the real thermodynamic cycles. An energetic and exergetic analysis is then developed to identify performance criteria (first law and seceond law efficiencies, specific energy…) as well as possible improvement of the basic cycle.
1) Elements of thermodynamics : first & second law, thermodynamic state functions, reversible & irreversible processes.
2) Gas-turbines
3) Turbojet
4) Internal combustion engine
5) Steam-turbines
6) Frigorific engine

Modélisation et analyse d’écoulements 1
Modélisation et analyse d’écoulements 2,
Heat and Mass transfers