ENGINEERING TRIPOS PART IB - 2012/2013
PAPER 4 - Thermofluid Mechanics
Leaders: Dr MP Juniper / Dr R Miller / Dr S Scott
Timing: Weeks 1-5 Michaelmas term (Dr MP Juniper),
week 6-8 Michaelmas and weeks 1-2 Lent term (Dr R Miller), weeks 3-5 Lent term (Dr S Scott)
Structure: 26 lectures, 2 lectures/week
The aims of the course are to:
- Review inviscid flow in three dimensions and derive the Euler equation.
- Examine the effects of viscosity on fluid flow.
- Introduce the phenomena of laminar and turbulent flow and of boundary layers.
- Explore the issues associated with scaling fluid flows and conducting model tests.
- Introduce the concept of availability.
- Show how irreversibilities affect the performance of gas power cycles.
- Introduce the properties of working substances other than ideal gases.
- Describe and analyse simple steam power plant, including the effect of irreversibilities
- Introduce and analyse refrigeration and heat pump cycles.
- Describe how to evaluate the properties of gas and gas/vapour mixtures.
- Show how the First Law may be applied to Combustion
- Develop analysis tools for 1D heat condition, and simple transient conduction problems.
- Examine heat transfer by convection.
- Introduce heat transfer by thermal radiation, including radiation in the environment.
- Describe common types of heat exchanger, and perform an elementary analysis of performance
At the end of the course students should be able to:
- Be able to set up the equations governing laminar viscous flow, and solve them for simple problems.
- Understand how irreversibilities arise in fluid flow and be able to make estimates of loss, drag, etc.
- Describe qualitatively the basic characteristics of boundary layers in internal and external flows.
- Understand the relevance of non-dimensional groups in determining the qualitative nature of fluid flow and how to apply this to model testing.
- Understand the effects of irreversibilities in gas, steam power cycles, and heat pump/refrigeration cycles.
- Understand and be able to use tables of properties for common working substances.
- Understand how to evaluate the properties of arbitrary mixtures of perfect gases, and gas/vapour mixtures, and apply this understanding to problems in psychrometry and combustion.
- Be able to analyse simple problems in conduction, convection and radiation heat exchange.
- Understand the physical principles underlying heat transfer correlations and be able to use these to estimate heat transfer coefficients.
Fluid Mechanics: lectures 1-10
1. Properties of a fluid (1L)
- Molecular picture vs. continuum picture
- Partial derivatives
- Law of conservation of mass
- Incompressible flow
2. Incompressible inviscid flow (1L)
- The material derivative, D/Dt
- Euler's equation
- Bernoulli's equation
- Streamline curvature
- Determination of the pressure field from the streamlines of a flow
3. Incompressible viscous flow and boundary layers (2L)
- Viscosity: momentum transfer through molecular motion
- Couette flow and Poiseuille flow
- The Navier-Stokes equation
- Boundary layers
- Pressure gradients in boundary layers
- Boundary layer separation
4. Turbulence and the Pipe Flow Experiment (1L)
- Laminar flow in a pipe with circular cross-section
- Turbulent flow
- Mixing, momentum transport and eddy viscosity
5. Network analysis (1L)
- Static pressure and stagnation pressure
- Stagnation pressure losses across pipe components
- Stagnation pressure changes across pumps and compressors
- Network analysis
6.The Boundary Layer Experiment (1L)
- Reynolds number in a boundary layer
- Transition to turbulence in a boundary layer
- Effect of turbulence on a boundary layer
- Comparison of transition and separation
- Boundary layer re-attachment
7.The External Flow and Drag Experiment (1L)
- Lift and drag
- Flows at very low Reynolds number (creeping flow)
- Flows at low Reynolds number
- Flows at high Reyholds number
- Mechanisms of drag reduction
- Vortex shedding
- Inviscid flow and Hele-Shaw cells
8.Dimensional analysis, scaling and model testing (1.5L)
- Dimensional analysis: the philosopher's, Mathematician's and engineer's approach
- Orific plate example
- Aeroplane example
- Ship example
9.Introduction to Compressible Flow (0.5L)
- The Steady Flow Energy Equation
- Stagnation enthalpy and stagnation termperature
- Viscous dissipation and irreversibility
- Transfer form thermal energy to mechanical energy.
- Incompressible flows and stagnation pressure.
Thermodynamics: lectures 11 - 20
1.Introduction, review of previous material (1L)
- 1st & 2nd laws applied to steady flow device
- The ‘quantity’ and ‘quality’ of energy
- Irreversible entropy creation
- Examples of steady-flow devices
2. Maximum available power(1L)
- The different value of work and heat
- The maximum available power in a steady flow device
- The dead state
- How to apply availability to a steady flow device
- Lost power potential due to irreversible
3. Gas turbines(1L)
- Compressor and turbine irreversibilities
- Combustion changes in gas composition
- First law analysis of gas turbines
- Land based gas turbines and aeroengines
- Second law analysis of gas turbines:Availability
4. Working fluids(2L)
- p-v-T data for water and normal fluids
- Saturation lines, the triple point, the critical point
- Evaluating properties, dryness fraction
- Working with tabulated data
5. Power Generation (2L)
- Vapour power plant
- The Rankine cycle
- Reheating and superheating
- Isentropic efficiency
- Combined gas-vapour power cycles
- 1st law analysis of Rankine cycles
- 2nd law analysis of Rankine cycles
- HRSG analysis
6.Refrigeration cycles (1L)
- Refrigerators and heat pumps
- Coefficient of performance
- Real refrigeration cycles
- The T-s and p-h diagram
- Choice of refrigerants
- Practical cycles
7. Properties of Mixtures (1L)
- Describing mixture composition
- Dalton's law
- Amagat's law
- p,v,T relations for a mixture of ideal gases
- Evaluations of U,H & S for a mixture of ideal gases
- Analysis of gas,vapour mixtures
- Saturated mixtures
- Specific humidity & relative humidity
- Dew point
- Air conditioning
8. Combustion (1L)
- Chemical equations
- Lambda and equivalence ratio
- First law applied to combustion
- Phase change of reactants
Heat transfer: lectures 21 - 26
1. Heat Transfer by Conduction (2L)
- Conduction in solids - Fourier's law
- Energy balance in 1D
- Overall resistance to heat transfer
- Dimensional analysis
- Lumped heat capacity model
2. Heat Exchangers (0.5L)
- Description of major types
- Analysis, effectiveness, LMTD
3. Heat Transfer by convection (2L)
- Energy considerations for flows with heat transfer
- Forced convection, Reynolds and Prandtl, Nusselt and Stanton numbers
- Reynolds analogy
- Natural convection. Grashoff and Rayleigh numbers
4. Heat Transfer by Radiation (1.5L)
- Radiation from black bodies
- Emissivity and radiation from grey bodies
- View factors
- Radiation networks.
Please see the Booklist for Part IB Courses for references for this module.
Last updated: September 2012