Air Engine (eBook)

Stirling Cycle Power for a Sustainable Future

Allan J. Organ (Autor)

eBook Download: PDF | EPUB

2007 | 1. Auflage
306 Seiten
Elsevier Science (Verlag)
978-1-84569-360-2 (ISBN)

Infos

Two centuries after the original invention, the Stirling engine is now a commercial reality as the core component of domestic CHP (combined heat and power) - a technology offering substantial savings in raw energy utilization relative to centralized power generation. The threat of climate change requires a net reduction in hydrocarbon consumption and in emissions of 'greenhouse' gases whilst sustaining economic growth. Development of technologies such as CHP addresses both these needs.
Meeting the challenge involves addressing a range of issues: a long-standing mismatch between inherently favourable internal efficiency and wasteful external heating provision; a dearth of heat transfer and flow data appropriate to the task of first-principles design; the limited rpm capability when operating with air (and nitrogen) as working fluid. All of these matters are explored in depth in The air engine: Stirling cycle power for a sustainable future. The account includes previously unpublished insights into the personality and potential of two related regenerative prime movers - the pressure-wave and thermal-lag engines.

• Contains previously unpublished insights into the pressure-wave and thermal-lag engines
• Deals with a technology offering scope for saving energy and reducing harmful emissions without compromising economic growth
• Identifies and discusses issues of design and their implementation

Allan J. Organ, PhD, Deng, ScD, FIMechE is known internationally for his work on Stirling engines. He is author of some 50 technical papers and four highly regarded texts on regenerative thermal cycles. The material and its treatment reflect experience accumulated over four-and-a-half decades of university research in the UK, Canada and South America.

Textauszug

Notation

AC

cross-sectional area of compression cylinder

m2

Aff

free-flow area - cross-sectional area of flow passage, e.g. of regenerative annulus

m2

a

local isentropic acoustic speed √γRT or √RT as per context

m/s

b

height of flow passage in direction of axis of spiral

m

a, b

coefficients of equation - defined in text

(as required)

c

local acoustic speed, isentropic√γRT or isothermal √RT as per context

m/s

c

radial gap between concentric cylinders

m

cp, cv

specific heat at constant pressure/volume

J/kgK

cw

specific heat of material forming matrix of regenerator

J/kgK

d

diameter

m

D

internal diameter of inlet manifold

m

D

total or substantial derivative ∂/∂t + u∂/∂x

s−1

d

diameter

m

dw

diameter of individual wire

m

F

friction term 2u¯2Cfsignu¯/rh

m/s2

f

cyclic frequency

s−1

g

mean mass velocity ρu based on free-flow area

kg/m2s

G

mean mass velocity ρu based on frontal area

kg/m2s

h

coefficient of convective heat transfer

W/m2K

k

thermal conductivity

W/mK

L

overall length of flow passage

m

Lx

length of flow passage of specified exchanger

m

Lo

piston-face to piston-face linear distance at crank angle datum

m

Lr, Lreg

regenerator flow passage length

m

Lref

reference length – equal to SW1/3

m

m

variable mass (of working fluid)

kg

m'

mass rate, dm/dt

kg/s

mw

mesh number – number of wires/m

m−1

P, Q

coefficients defined in text

(as required)

p

(absolute) pressure

Pa

pw

wetted perimeter

m

qs

heat shuttled per cycle

J

q'

heat rate per unit mass

W/kg

QC

heat rejected (from compression space) per cycle

J

QE

heat input (to expansion space) per cycle

J

R

specific gas constant

J/kgK

r

radial coordinate

m

r

crank-pin offset (piston semi-stroke)

m

rh

hydraulic radius – (wetted volume)/(wetted area)

m

rpm

revolutions per minute

min−1

s

coordinate in peripheral direction = rϕ

m

t

time

s

t

thickness of separating plate, or radial thickness (e.g.) of displacer shell

m

tc, td

radial thickness of wall of displacer/cylinder

m

T

(absolute) temperature

K

T

torque

Nm

Ta

local temperature of air stream

K

TC

temperature at ambient end of regenerator

K

TE

temperature at expansion end of regenerator

K

Tex

local temperature of exhaust stream

K

Tg

local, instantaneous absolute temperature at point in fluid/enclosure element

K

Tsu

Sutherland temperature

K

Tw

local, instantaneous absolute temperature at point in matrix or at enclosure wall

K

Twc

local, instantaneous temperature at given axial location on the cylinder

K

Twd

local, instantaneous temperature at given axial location on the displacer

K

u, v

local, instantaneous particle velocity in x and r coordinate directions respectively

m/s

u

(in the context of the Method of Characteristics) one-dimensional (slab-flow) velocity at a point in physical and state planes

m/s

u

mean mass velocity or bulk velocity, m'/ρAff

m/s

u

(in the context of the Method of Characteristics) mean value of u between two adjacent points on integration mesh

m/s

ud

instantaneous velocity of displacer

m/s

v

variable volume

m3

V

variable volume

m3

VC

amplitude of volume variation in compression space

m3

VE

amplitude of volume variation in expansion space

m3

Vsw

swept volume

m3

w

width of flow passage measured in radial direction

m

W

work per cycle

J

x

linear distances in x coordinate direction

m

ΔΤ

local, instantaneous difference T – Tw between temperature of gas and that of immediately adjacent solid element

K

β

angular rotation of fluid filament within flow passage of regenerator gauze aperture

–

δ*

displacement thickness (of boundary layer)

–

ϕ

angular coordinate

–

μ

coefficient of dynamic viscosity

Pa s

ρ

density

kg/m3

ρw

density of parent material of regenerator matrix

kg/m3

θ

momentum thickness (of boundary layer

m

ω

angular speed

s−1

Dimensionless variables (NB: dimensionless parameters listed below)

f

pressure coefficient p/12ρu2

–

F

number of degrees of freedom (of planar mechanism)

–

H

shape factor associated with boundary layer

–

J

number of joints (in planar mechanism)

–

L

number of binary, ternary, etc., links (forming planar mechanism

–

m

momentum thickness variable

–

Ma	Mach number...

Produkt-Details

• Erscheint lt. Verlag: 28.8.2007
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Thermodynamik
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• ISBN-10: 1-84569-360-4 / 1845693604
• ISBN-13: 978-1-84569-360-2 / 9781845693602