Finn Andersen, 2012 1

TRC2200 - Thermofluids Summary Notes Contents Thermo-fluids ................................................................................................................... 2

Intensive and Extensive Properties ........................................................................................ 2

Systems................................................................................................................................... 2

Gibbs’  Phase  Rule ................................................................................................................... 2

Processes ................................................................................................................................ 3

Mass conservation ................................................................................................................. 5

Energy Conservation .............................................................................................................. 5

Enthalpy .................................................................................................................................. 6

Ideal Gas Equations of State .................................................................................................. 7

Nozzles/Diffusers.................................................................................................................... 8

P-V Diagrams .......................................................................................................................... 8

Vapour Quality ....................................................................................................................... 9

Diesel Engine Cycle ................................................................................................................. 9

Heat Engine .......................................................................................................................... 10

Hydrostatics ................................................................................................................... 10

Hydrostatic Forces on Flat Surfaces ..................................................................................... 11

Hydraulic/Pneumatic System ............................................................................................... 12

Hydrostatic Forces on Submerged Curved Surfaces ............................................................ 12

Multilayered Fluid ................................................................................................................ 13

Buoyancy and Stability ......................................................................................................... 13

Stability of Immersed and Floating Bodies .......................................................................... 14

Fluid Power .................................................................................................................... 15

Forces in Double-acting cylinders ........................................................................................ 15

Bernoulli Equation ................................................................................................................ 15

Static and Dynamic Pressure ................................................................................................ 16

Correction Factor ................................................................................................................. 16

Head concept ....................................................................................................................... 17

Fluid Friction ......................................................................................................................... 17

Turbulence ........................................................................................................................... 19

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Mass conservation

Energy Conservation Mechanical Energy

Total Energy Equal to mechanical energy + internal energy U

x Internal energy usually increases with temperature for single-phase systems x Internal energy can change at fixed temperature and pressure during phase change.

Forms of work:

�̇� = �̇�

�̇� = 𝜌�̇� = �̇�𝑣

�̇� = 𝑣𝑜𝑙𝑢𝑚𝑒𝑡𝑟𝑖𝑐  𝑓𝑙𝑜𝑤  𝑟𝑎𝑡𝑒 = 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 × 𝐴

�̇� = 0  𝑓𝑜𝑟  𝑐𝑙𝑜𝑠𝑒𝑑  𝑠𝑦𝑠𝑡𝑒𝑚

For steady state system, mass flow rate in = mass flow rate out.

Specific

Boundary Work Shaft Work (rotary)

Finn Andersen, 2012 6

So boundary work is area under quasi-static process curve on P-v diagram:

Heat and Entropy

Heat in a quasi-static process is related to temperature and entropy in a system.

Closed System Conservation

Enthalpy

In an adiabatic process, Q=0.

x Hence a quasi-static adiabatic process is isentropic (entropy constant)

Heat Transfer Electrical work Shaft work Boundary Work

Specific (J/kg)