文档介绍：The Application of Turbomachinery to Reciprocating Engines
涡轮机械在往复式发动机上的应用
Chapter 6
第6章
Matching 4-Stroke Diesels
与四冲程柴油机匹配
Volumetric Efficiency
容积效率
The volumetric efficiency is defined as; 充气效率的定义如下
where:
D = Displacement per cycle [length3/cycle] 一个工作循环的排量[长度3/循环次数]
N = Engine speed [rev/time] 发动机转速[转/分]
NRPC = Number of revolutions per cycle [2 for a four-stroke engine]每循环活塞往复运动次数[二或四冲程]
where:
vol = Volumetric Efficiency [dimensionless]容积效率[无量纲]
min = Net mass flow rate into engine cylinders [mass/time]进入气缸的净质量流量[质量/时间]
ref = Reference density [mass/length3]参考密度[质量/长度3]
VDR = Volumetric displacement rate [length3/time]单位时间体积排量[长度3/时间]
The volumetric displacement rate is calculated by;单位时间体积排量按下面的公式计算
.
vol
in
ref
=
actual air
mass flow
ideal air
mass flow
=
m
*
VDR
VDR
=
D
*
N
NRPC
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Volumetric Efficiency (continued)
容积效率
The reference density is calculated from the ideal gas law (P*v = m*R*T);
参考密度按照理想气体状态方程计算
where:
R = Gas constant for air [(length*force)/(mass*temperature)]空气气体常数
Pref = Reference pressure [mass/length2] (Ref conditions in the inlet manifold)
参考压力（在进气管状态下）
Tref = Reference temperature [temperature] 参考温度
Substituting these relationships into the definition of volumetric efficiency gives;
把这些参数带入上述充气效率公式中则有:
or, solving for min gives:或者，求解min
.
.
.
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û
ù
ê
ë
é
´
´
´
´
´
=
ref
ref
in
vol
P
N
D
T
m
NRPC
R
η
ú
û
ù
ê
ë
é
´
´
´
´
´
=
ref
ref
vol
in
T
NRPC
R
P
N
D
η
m
ú
û
ù
ê
ë
é
´
=
ref
ref
ref
T
R
P
ρ
Breathing Lines (Four-Stroke Diesel Engine Only)
Given the equation derived from the definition of Volumetric Efficiency;由容积效率定义得出方程式:
Make the following assumptions/approximations;做下面的假设/近似值
vol = a constant (somewhere between .88 and .95) 常量()
Pref = Pamb * (Compressor Pressure Ratio) = Pamb*PRc压气机压缩比
Tref =