Design and Simulation of Two Stroke Engines

gas constant/universal gas constant, 64
mass ratios (oxygen, nitrogen), 65
molal enthalpy, internal energy, 65
molal specific heat (at constant pressure, volume),
65
molal specific heats (oxygen, nitrogen), 66
molecular weight, average, 65
specific heat (at constant pressure, temperature),
64
specific heats ratio, 64
Gaussian Elimination method
for wave reflection at contractions in pipes, 107
for wave reflection at outflow from a cylinder,
132
General Motors
diesel road engines, 3
Geometric compression ratio, defined, 8
GPB engine simulation model
introduction
unsteady gas flow computation, discussion of,
142-144
basis of GPB model, 144
computational model, criteria for, 143-144
duct meshing for pressure wave propagation,
144-145
four-stroke engines, applicability to, 143
GPB model computational requirements, 145
physical parameters (e.g., pressure, density,
etc.), 145
pressure wave propagation within mesh J
(illus.), 146
Reimann variables, use of, 142
superposition pressure amplitude ratio, 145
air flow into an engine
B parameter, assessment of, 167
delivery ratio, 168
scavenge ratio, 168
total mass air flow, 167
computation time, comments on, 191-192
concluding remarks about, 192
correlation with QUB SP experimental appara
tus. See under QUB (Queen's University of
Belfast)
friction and heat, changes due to, 151
inter-mesh boundaries (reflections after time
stop)
introduction, 151-152
603
Index
adjacent meshes in differing discontinuities
(diagram), 152
parallel ducting, 152-153
tapered pipes, 153-154
interpolation procedure (wave transmission
through a mesh)
gas dynamic parameters, values of, 149-150
groupings of variables ("known" terms), 148
pressure amplitude ratios, determination of,
148-149
propagation velocities, 147
singularities during interpolation procedure,
150
values of lengths xp> xq 147
mass/energy transport along duct (after time
stop)
introduction, 156
First Law of Thermodynamics, application of,
156-158, 160
gas dynamic parameters, values of (four
cases), 158-159
"hand" of the flow, 157
mesh J, energy flow diagram for, 157
new reference conditions, determination of,
161-162
purity in mesh space J, 161
system state, change of, 160
transport at mesh J (four cases), 156-157
thermodynamics of cylinders and plenums (during
time step)
introduction, 162
boundary conditions, application of, 163-164
First Law of Thermodynamics, application of,
163-165
heat transfer coefficient, determination of
(discussion), 164
heat transfer from/to plenum, expression for,
164
new gas properties, purity, 166
new reference conditions (for next time step),
166
open cycle flow through cylinder (thermodynamic
diagram), 163
sign conventions, importance of, 163
system state, change of, 164
system temperature, solution for, 165
time interval, selection of, 146