In this post, we will discuss the Top Mechanical Engineering Interview Questions and Answers. These Questions and Answers may be helpful in the interviews.
Mechanical Engineering interview Questions and Answers
Question: what is the mechanical advantage of a double pulley.
Answer: A double pulley system- In the double pulley system, we use two pulleys, a rope runs around them to lift a load. To reduce the amount of effort needed we use two or more pulleys. We use double pulleys to increase the mechanical advantage. Higher the mechanical advantage results in the fewer efforts require to move the same load. Mechanical Advantage of the double pulley system is 2, hence it only takes half the effort to move a load.
Mechanical advantage is calculated by counting the number of rope sections that support whatever load we are lifting.
Question: Define Extrusion?
Answer: The Process that is used to create objects of the fixed cross-sectional profile is known as Extrusion.
Question: Define knurling?
Answer: The Knurling is a manufacturing process. knurling is mainly a roughening of the surface and knurling is done for a better gripping surface, knurling is typically conducted on a lathe by which a pattern of crossed, angled or straight lines are rolled into the material.
Question: Define Ultimate tensile strength?
Answer: Ultimate Tensile Strength is the maximum stress that a material can handle before breaking.
Question: What are the machining processes and its various types?
Answer: The Processes in which material is removed from a workpiece are called as machining processes.
Machining Processes are classified into two categories.
Conventional Machining or traditional Machining:
Conventional machining processes are the processes by which the machine tools touch the job and cut the material according to the
requirement to give the shape & size.
These are done on conventional machines.
Example-lathe, drilling, turning,
milling, shaping, grinding
Non- conventional Machining:
The nonconventional machining processes are those in which there is no direct contact between tools and the workpiece. In the nonconventional Machining Process, a form of energy is used to remove the unwanted material from the workpiece.
These are done by the applications of those methods which
are well developed
Example:-ECM, USM, AJM, EDM, WJM etc.
Question: Explain the working of Centrifugal Pump?
Answer: Centrifugal pumps are used to raise the pressure of a liquid or water. The heart of the system is the impeller, the impeller is always immersed in the water when impeller rotates, the fluid (water) surrounding it also rotates. This provides centrifugal force to the water particles, and water moves radially out, so at the discharge side, the rotational mechanical energy will be transferred to the water or fluid, this will result in the rise of the Pressure and velocity of water, and a negative pressure will be induced at the suction side, so the system will suck the fresh water to fulfil this pressure requirement on the suction side and this process continues.
A centrifugal pump containing two or more impellers is known as the multistage centrifugal pump.
Question: How will we know in which direction a liquid is flowing in a pipe?
Answer: The direction of liquid flow in a pipe is from a high-pressure region to a low-pressure region.
Question: Why the vacuum balancing line is required in the CEP Pump?
Answer: In CEP suction the Vacuum balancing line is required to avoid cavitation
Cavitation is the formation of vapor bubbles within a liquid in low-pressure regions.
And balancing line is required to provide positive suction to CEP. As CEP takes suction from HOTWELL, which is in a vacuum, So, there will be negative pressure at suction. As we all know that the boiling point of water is less at low pressure. Hence the condensate will try to vaporize at low pressure this will cause cavitation ( which we have discussed earlier) and the pump will get damaged.
Hence a vacuum balancing line is provided at CEP suction to remove vapors which will directly go to the condenser.
Question: what is the difference between pipes and tubes?
Answer: Pipes are used to transporting or carrying something like- fluid, steam, gas etc and tubes are used to construct something.
pipes are measured by internal diameter and tubes are measured by outer diameter.
Outer Diameter= Inner Diameter + 2* Wall Thickness.
The tube is a long hollow material with the capacity to bent at any point. while pipe has no capacity to bend we have to use an elbow to bend it.
Question: Define Nominal Bore (NB) & Schedule for a pipe?
Answer: The pipes are used to carry fluid, steam and other process parameters so internal diameter is a critical parameter. This critical Parameter is referred to as Nominal Bore (NB).
Wall thickness is expressed in “schedules”, and known as pipe schedules.
The formula for calculating
Schedule number= 1000x (P/S)
Where P is internal Pressure in PSI & S is allowable fiber stress.
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