HOW TO PREPARE FOR GATE AND ENGINEERING SERVICES EXAMINATION

Dear friends if you want to get single digit rank in Gate or Engineering service examination then try to adopt following habits in your daily life:

a)   Make habits, go to bed around 11:30 pm night and try to get-up around 6 o-clock morning if possible else sleep 7 hours daily.

b)     Make a daily routine and follow it.

c)     Do half an hour physical exercise daily.

d)     Set your target for single digit rank, never thought negative in your mind.

e)      Do hard labour because hard labour beats talent when talent does not work hard.

f)      Read thoroughly 6-7 hours in a day there is no short-cut path for single digit rank. If your doubt is not clear with self study then take help from your friends or internet or your teacher.

g)     Try to take balance diet.

h)     Do not get nervous with time or syllabus.

i)       Always kept your mind cool and calm.

j)       Make own notes of all subjects for quick revision.

k)    Solve 20 years previous question papers of gate, engineering services and UPSC of Mechanical Engineering.

l)       Enjoy all the moments in your life and be happy always.

Basics Definitions of Rotating Equipment

Fan is a gas pump with relatively low pressure rise and high flow rate. Examples include ceiling fans, house fans, and propellers.

Blower is a gas pump with relatively moderate to high pressure rise and moderate to high flow rate. Examples include centrifugal blowers and squirrel cage blowers in automobile ventilation systems, furnaces, and leaf blowers.

Compressor is a gas pump designed to deliver a very high pressure rise, typically at low to moderate flow rates. Examples include air compressors that run pneumatic tools and inflate tires at automobile service stations, and refrigerant compressors used in heat pumps, refrigerators, and air conditioners.

Pump is a device which adds energy to a fluid, resulting in an increase in fluid pressure, not necessarily an increase of fluid speed across the pump.

Turbine is a device which extracts energy from a fluid, resulting in a decrease of fluid pressure, not necessarily a decrease of fluid speed across the turbine.

COOLING TOWER MATERIAL BALANCE

Quantitatively, the material balance around a wet, evaporative cooling tower system is governed by the operational variables of make-up flow rate, evaporation and windage losses, draw-off rate, and the concentration cycles.

Air Flow Generation Methods in Cooling Tower:

With respect to drawing air through cooling tower, there are three types of cooling towers:

1)      Natural Draft: Utilizes buoyancy via a tall chimney. Warm, moist air naturally rises due to the density differential compared to the dry, cooler outside air. Warm moist air is less dense than drier air at the same pressure. This moist air buoyancy produces an upwards current of air through the tower.

COOLING TOWER

A cooling tower is a heat rejection device which rejects waste heat of water to atmosphere through cooling of a water stream to a lower temperature. Cooling towers may either use evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or, in the case of closed circuit dry cooling towers, rely solely on air to cool the working fluid to near the dry-bulb air temperature.

BASICS OF AIR HANDLING UNIT AND ITS DESIGN

In this article we know the followings:

1)     Know the different types of AHUs, and their basic anatomy

2)     Understand the codes and standards that govern AHU specification

3)     Learn about how energy can be saved in HVAC systems that use AHUs.

A basic definition of an air handling unit (AHU) might be “a box with a fan, coils, and filters.” From there it gets considerably more complicated.

Air Handling Unit

Air Handling Unit

There are basically two types of Air Handling Unit that are in used and they are the "Draw-Through" or "Blow-Through". 

In Draw-Through type, the fan pulls the air through the mixing box, filters and cooling coil before discharging it from the fan outlet to the space to be conditioned or to the ducting network. The design can be vertical or horizontal. In this case, the section before the fan has negative pressure.