MOOC Hydraulic Power(Chang'an University)1461589169 最新慕课完整章节测试答案

Test

1、单选题：
Which of the following is not an advantage of the hydraulic system ( )​​
选项：
A: With the same size structure, the hydraulic system can deliver greater power
B: Small inertia, rapid starting and braking, smooth movement
C: Convenient for stepless speed regulation, wide speed regulation range
D: Higher transmission efficiency
答案: 【 Higher transmission efficiency】

2、单选题：
Which of the following is not a disadvantage of the hydraulic system ( )​​
选项：
A: Cannot be used for high precision transmission
B: Overload protection is not easy to achieve
C: High precision requirements for component manufacturing
D: Difficulty in troubleshooting
答案: 【 Overload protection is not easy to achieve】

3、单选题：
‍Which of the following is a hydraulic power element （）‍
选项：
A: Pump
B: Motor
C: Cylinder
D: Relief valve
答案: 【 Pump】

4、单选题：
​Which of the following is a hydraulic control element ( )‎
选项：
A: Pump
B: Motor
C: Cylinder
D: Relief valve
答案: 【 Relief valve】

5、单选题：
Which of the following is a rotational hydraulic execute element ( )‍‎‍
选项：
A: Pump
B: Motor
C: Cylinder
D: Relief valve
答案: 【 Motor】

6、判断题：
‏Hydraulic system cannot be used for high precision transmission.​
选项：
A: 正确
B: 错误
答案: 【 正确】

7、判断题：
‌With the same size structure, the hydraulic system can deliver greater power.‍
选项：
A: 正确
B: 错误
答案: 【 正确】

8、判断题：
‎The hydraulic system has high precision requirements for component manufacturing.‌
选项：
A: 正确
B: 错误
答案: 【 正确】

9、判断题：
‏It is difficult in troubleshooting of hydraulic system.​
选项：
A: 正确
B: 错误
答案: 【 正确】

10、判断题：
​Hydraulic system is convenient for stepless speed regulation.‍
选项：
A: 正确
B: 错误
答案: 【 正确】

11、判断题：
‎Hydraulic system has high power transmission efficiency. ‏
选项：
A: 正确
B: 错误
答案: 【 错误】

12、判断题：
‌ Water can be used as hydraulic transmission media.​
选项：
A: 正确
B: 错误
答案: 【 错误】

13、判断题：
‏Hydraulic motor gives rotationally movements in hydraulic system. ‍
选项：
A: 正确
B: 错误
答案: 【 正确】

14、判断题：
‏Hydraulic cylinder is a power element in hydraulic system.‎
选项：
A: 正确
B: 错误
答案: 【 错误】

15、判断题：
​Hydraulic media can be any fluid.‎
选项：
A: 正确
B: 错误
答案: 【 错误】

16、填空题：
The hydraulic transmission system is composed of the following parts, which are ？‏
答案: 【 __power element__, __execution element__ and __control element__, __auxiliary element__ and __working medium__.

​】

17、填空题：
​The hydraulic power element convert the ____ to ____.‏
答案: 【 mechanical power hydraulic power】

18、填空题：
‍The execution element convert the ____ to ____.‏
答案: 【 hydraulic power mechanical power】

19、填空题：
‏Hydraulic pump is a typical _____ in hydraulic system .‏
答案: 【 power element】

20、填空题：
‍Hydraulic cylinder is a typical ____ in hydraulic system .‏
答案: 【 power element】

21、填空题：
‏Hydraulic cylinder outputs ____.‏
答案: 【 linear movement】

22、填空题：
‏Hydraulic motor outputs ____.‎
答案: 【 rotational movement】

23、填空题：
‏Hydraulic control element regulate the  ____ 、___ and ____ of the hydraulic oil .​
答案: 【 pressure flow rate flow direction】

24、填空题：
‌Hydraulic transmission is of  ____ efficiency.‌
答案: 【 low】

25、填空题：
‏Hydraulic transmission is ____ to be protected from overload.​
答案: 【 low】

Test

1、单选题：
​Liquid is a
continuous medium. That is, the motion parameters of liquid can be regarded as
a continuous function of (    ), and it is possible to use analytical mathematics
to describe its motion law.‍
选项：
A: It has nothing to do
with time and space
B: Time and space
C: Just time
D: Just space
答案: 【 Time and space】

2、单选题：
In the case of (  ), the influence of liquid compressibility on performances of hydraulic system cannot be ignored.​
选项：
A: When studying static performances of system
B:  When studying dynamic performances of system
C: Under high pressure
D: Under low pressure
答案: 【  When studying dynamic performances of system】

3、单选题：
(   ) has a great influence on the compressibility of liquid.‏
选项：
A: Gas mixed with liquid
B: Impurities mixed into liquid
C: The viscosity of liquid
D:  Density of liquid
答案: 【 Gas mixed with liquid】

4、单选题：
The hydrostatic pressure is always along the (  ) direction of liquid acting surface.‏
选项：
A: Tangent
B: Outer normal
C: Not sure
D: Inner normal
答案: 【 Inner normal】

5、单选题：
The relationship between relative pressure, absolute pressure and atmospheric pressure is(   ).‏
选项：
A: Relative pressure = absolute pressure + atmospheric pressure
B: Absolute pressure = relative pressure-atmospheric pressure
C: Atmospheric pressure = absolute pressure + relative pressure
D: Relative pressure = absolute pressure-atmospheric pressure
答案: 【 Relative pressure = absolute pressure-atmospheric pressure】

6、单选题：
A curve of the motion state of various particles in liquid flow at a time is called (    ).‍​‍
选项：
A: Trace
B: Waterline
C: Quality line
D: Streamline
答案: 【 Streamline】

7、单选题：
Since any mass point in the flowing liquid can only have one speed at a certain time, there is (    ) between the streamlines.‌‏‌
选项：
A: Impossible to intersect, may make a sudden turn
B: It is impossible to intersect, and it is impossible to make a sudden turn
C: It may intersect, but it is impossible to make a sudden turn
D: May intersect, or suddenly turn
答案: 【 It is impossible to intersect, and it is impossible to make a sudden turn】

8、单选题：
The velocity of the actual liquid on the flow section (    ).‎​‎
选项：
A: Each point is different, showing a parabolic distribution
B: The points are different, distributed in a triangle
C: Each point is different and the distribution law is uncertain
D: All points are the same
答案: 【 Each point is different, showing a parabolic distribution】

9、单选题：
When liquid flows, the particles have no lateral pulsation and do not interfere with each other. The hierarchical flow state that is oriented and not mixed is called (    ).‍‍‍
选项：
A: Turbulence
B:  Laminar flow
C: Advection
D: Turbulence
答案: 【  Laminar flow】

10、单选题：
The energy loss of liquid in the equal-diameter straight pipe along the flow direction due to the internal friction between the fluid layers is called (   ).‎‌‎
选项：
A: Energy loss along the way
B: Local energy loss
C:  Pressure loss
D: Flow loss
答案: 【 Energy loss along the way】

11、多选题：
Which of the following characteristics does liquid have:(    )‎‎‎
选项：
A: Homogeneity
B: Continuity
C: Not tensile
D: Easy flow
答案: 【 Homogeneity;
Continuity;
Not tensile;
Easy flow】

12、多选题：
The main function of the working medium in the hydraulic system is:(    ) ‌‌‌
选项：
A: Take away heat
B: Take away dirt
C: Transfer energy
D: Lubricate
答案: 【 Take away heat;
Take away dirt;
Transfer energy;
Lubricate】

13、多选题：
The commonly used forms of pressure units are:(    )‏
选项：
A: Force per unit area
B: Multiple of engineering atmospheric pressure
C: Liquid column height
D: Force per unit volume
答案: 【 Force per unit area;
Multiple of engineering atmospheric pressure;
Liquid column height】

14、多选题：
Whether liquid is laminar or turbulent is related to (    ).‍‍‍
选项：
A: Flow rate
B: Viscosity of liquid 
C: Pipe diameter
D: Density 
答案: 【 Flow rate;
Viscosity of liquid ;
Pipe diameter】

15、多选题：
Local energy loss will occur under the following conditions (    ).​‏​
选项：
A: The flow section is suddenly enlarged
B: There are various hydraulic components and accessories in the flow channel 
C: The flow section is suddenly reduced 
D: The flow channel is bent
答案: 【 The flow section is suddenly enlarged;
There are various hydraulic components and accessories in the flow channel ;
The flow section is suddenly reduced ;
The flow channel is bent】

16、判断题：
‌It has good chemical
stability, that is, it has good stability to heat, oxidation, hydrolysis and
shearing. It can maintain the original chemical composition after long-term
contact with air at high temperature and high-speed passage through the gap.​
选项：
A: 正确
B: 错误
答案: 【 正确】

17、判断题：
‎ In a closed container, the pressure exerted on
the boundary of a static liquid can be equally transmitted to all directions in
liquid. ​
选项：
A: 正确
B: 错误
答案: 【 正确】

18、判断题：
‍ In hydraulic transmission technology, the
static pressure caused by external force is much larger than the static
pressure caused by gravity, so the latter can usually be ignored. ‏
选项：
A: 正确
B: 错误
答案: 【 正确】

19、判断题：
‎ When liquid flows in a round pipe, the
velocity distribution in the turbulent flow state is more uniform than that in
the laminar flow state. ‏
选项：
A: 正确
B: 错误
答案: 【 正确】

20、填空题：
‌In the oil outlet pipeline of the pump, if the absolute pressure is 10MPa, the gauge pressure is (    )MPa.‏
答案: 【 9.9】

21、填空题：
‌In the suction pipe of the pump, if the absolute pressure is 0.07MPa, the vacuum is (   )MPa.​
答案: 【 0.03】

22、填空题：
‏The size of viscosity can be expressed by three methods: dynamic viscosity, (     ), and relative viscosity.‍
答案: 【 Kinematic viscosity】

23、填空题：
‏ In addition to moving in a certain direction when liquid flows, there is also a pulsating lateral velocity, which makes liquid particles interlaced and mixed with each other. This flow state is called (      ).​
答案: 【 Turbulence】

24、填空题：
​ According to the different causes, gap flow can be divided into three types: differential pressure flow, shear flow and (    ) flow.‌
答案: 【 mixing】

25、填空题：
‍ The large Reynolds number shows that the inertial force plays a leading role, and liquid flow is in (     ) state.‎
答案: 【 Turbulence】

26、填空题：
‍ Pressure loss during liquid flow can be divided into two categories, namely pressure loss along the way and (   ) Pressure loss.‎
答案: 【 Partial】

27、填空题：
‎ In the hydraulic system, the oil pressure rises sharply due to a sudden change in the working state of a certain component, and a high pressure peak is suddenly generated in an instant, and the damping fluctuation process of alternating rapid pressure rise and fall is called (     ).‏
答案: 【 Hydraulic shock】

28、填空题：
​ In liquid flow, due to the pressure drop, the phenomenon of bubble formation is collectively called the (   ） phenomenon.‎
答案: 【 Air pocket)】

29、填空题：
‎The effect of liquid viscosity is to hinder the flow of liquid, and the size of viscosity is measured by (   ).‏
答案: 【 Viscosity】

test

1、单选题：
Liquid