化工原理英文教材chapter2

If the suction pressure is actually less than the vapor pressure, cavitation will occur in the suction line, and no liquid can be drawn into the pump.
化工原理 Principles of Chemical Industry
Transportation and metering of fluids
The engineer is concerned with practical problems in transporting fluids from one place to another and in measuring their rates of flow.
Such devices increase the mechanical energy of the fluid.
The energy may be used to increase the velocity, the pressure, or the elevation of the fluid.
W
pb
gZb
ub2 2
pa
gZa
ua2 2
(8-1)
The equation(8-1) can be divided by g, gives
H
pb
g
Zb
ub2 2g
pa
g
Za
ua2 2g
(8-1a)
The quantity H is called developed (total) head, in which each term has the dimension of length.

Bingham plastic
The rheological behavior of liquids called non-Newtonian.
o
du/dy
Figure 3 Shear stress versus velocity gradient for non-Newtonian fluids.
turbulent flow: The fluid moves erratically in form of crosscurrents and eddies.
Gas :
kinematic viscosities increase more rapidly with temperature than does the absolute viscosity.
Turbulence
It has long been known that a fluid can flow through a pipe or conduit in two different ways:
One-dimensional flow
Velocity is a vector, but only one velocity component is required. This simple situation is called Onedimensional flow.
Example: steady flow through straight pipe.
The assumptions of steady one-dimensional flow is the basis of following discussion. All we will talk about in this course belong to one dimensional steady flow

Chemical Equilibrium and KineticsLesson2化学平衡和动力学A major objective of chemist is to understand chemical reactions, to know whether under a given A1be reaction will whether a given substances will react when mixed, to determine of set conditions twobefore will proceed a given reaction to predict the extent to which exothermic or endothermic, andequilibrium is established.确知道在一组给定的条件下两种物质混合时能否发生反应；化学家的一个主要目标是理解化学反应，定一个给定的反应是放热还是吸热；预测一个给定的反应在平衡前进行的程度。

2 An equilibrium state, produced as a consequence of two opposing reactions occurring simultaneously, is astate in which there is no net change as long as there is no change in conditions.这个状态就只要条件不发生改变，平衡状态是由两个对立反应同时发生产生的结果，在平衡状态下，不会有净变化。

from systems state of chemical how one predict the equilibrium 3 In this lesson it will be shownprovide states equilibrium how the experimental measurements on thermodynamic data, and converselyuseful thermodynamic data.平衡状态下的以及相反地，在这节课中，将会展示如何根据热力学数据来预测化学体系的平衡状态，实验测量值如何提供有用的热力学数据。

2.4 Hvv
t
2vvvH7H2vv37vH3(H0(.10711v78.72.gv071g2123.PH2241v.14Hv4.H02v54)v[4tmtH2237)27237w373ta321te.720r31713P3.v01a101p53P.o0r1k13Pg051w[0ma5 te3水 r v汽apkogr]水
nv pv p ng pg P p H 0.622 p (5 2) H=f（P，p）
P p
p=pv—partial pressure of water vapor in moist air, N/m2; pg—partial pressure of dry air in moist air; P—total pressure of moist air, N/m2.
Hs
0.622
ps P ps
(5 3)
ps f (t) Hs f (P,t)
Where p=ps=f(t), ps=vapor pressure of water, Hs=f(P, t)
15
•(2)Specific volume of moist air :
Specific volume of dry air:
(2)continuous and batchwise drying processes. (3)According to the heat transfer manners: 1)Indirect dryers/dryers in which heat is transferred to the
solid from an external medium(condensing steam, etc) 2)Convective/direct dryers/Dryers in which the solid is directly