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2 years ago

Which contribution of Science is the most important discovery of man? Explain why?

Engineering

1 answer:

Vsevolod [243]2 years ago

5 0

Answer:

<h2>The Invention of the Internal Combustion Engine (ICE)</h2>

Explanation:

The internal combustion engine is an engine in which ignition and combustion take place in the engine(in one place), the invention of the ICE was an integral part of the industrial revolution, as there was increasing demand for power, and manual labor could not suffice, especially during the mid 19 century.

The ICE made it possible for tasks that demand intensive power consumption to come through to reality, it was as a result of the invention of the ICE that road transportation was made easier for mankind, as the means of transport then was the use of beast of burden, now we have cars, airplanes ship, etc, essentially the invention of ICE reduced the tedious task man would have to engage in for his daily needs

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Air modeled as an ideal gas enters a combustion chamber at 20 lbf/in.2

motikmotik

Answer:

The answer is " $112.97 \ \frac{ft}{s}$ "

Explanation:

Air flowing into the $p_1 = 20 \ \frac{lbf}{in^2}$

Flow rate of the mass $m = 230.556 \frac{lbm}{s}$

inlet temperature $T_1 = 700^{\circ} F$

Pipeline $A= 5 \times 4 \ ft$

Its air is modelled as an ideal gas Apply the ideum gas rule to the air to calcule the basic volume v:

$\to \bar{R} = 1545 \ ft \frac{lbf}{lbmol ^{\circ} R}\\\\ \to M= 28.97 \frac{lb}{\bmol}\\\\ \to pv=RT \\\\\to v= \frac{\frac{\bar{R}}{M}T}{p}$

$= \frac{\frac{1545}{28.97}(70^{\circ}F+459.67)}{20} \times \frac{1}{144}\\\\=9.8 \frac{ft3}{lb}$

$V= \frac{mv}{A}$

$= \frac{230.556 \frac{lbm}{s} \times 9.8 \frac{ft^3}{lb}}{5 \times 4 \ ft^2}\\\\= 112.97 \frac{ft}{s}$

8 0

2 years ago

Consider a 2-shell-passes and 8-tube-passes shell-and-tube heat exchanger. What is the primary reason for using many tube passes

Maru [420]

Answer:

See explanation

Explanation:

Solution:-

- The shell and tube heat exchanger are designated by the order of tube and shell passes.

- A single tube pass: The fluid enters from inlet, exchange of heat, the fluid exits.

- A multiple tube pass: The fluid enters from inlet, exchange of heat, U bend of the fluid, exchange of heat, .... ( nth order of pass ), and then exits.

- By increasing the number of passes we have increased the "retention time" of a specific volume of tube fluid; hence, providing sufficient time for the fluid to exchange heat with the shell fluid.

- By making more U-turns we are allowing greater length for the fluid flow to develop with " constriction and turns " into turbulence. This turbulence usually at the final passes allows mixing of fluid and increases the heat transfer coefficient by:

U ∝ v^( 0.8 ) .... ( turbulence )

- The higher the velocity of the fluids the greater the heat transfer coefficient. The increase in the heat transfer coefficient will allow less heat energy carried by either of the fluids to be wasted ; hence, reduced losses.

Thereby, increases the thermal efficiency of the heat exchanger ( higher NTU units ).

5 0

2 years ago

Explain three (3) modes of heat transfer in air conditioning system.

LenKa [72]

Answer:

1. Conduction

2. Convection

3. Radiation

Explanation:

The 3 modes of heat transfer i an air conditioning system:

1. Conduction:

The transfer of heat by conduction takes place in solid and is when the conduction takes place as a result of direct contact in between the interacting material which transfer the heat energy from particle to particle thus conducting the heat through out the system.

2. Convection:

The other mode for the transfer of heat which takes place especially in fluids - gases and liquids is through the technique of convection in which the transfer of heat takes place by the circular motion of the atoms and molecules of the fluid which carries the heat energy and results in the distribution of the heated fluid in the entire system thus transferring all the heat energy in the entire system.

3. Radiation:

The third mode of heat transfer in the air conditioning system is through radiation. This method transfers the heat by making use of the electro-magnetic radiation in the infra red spectrum where the waves of the spectrum transfers the heat energy with the help of a medium or without any medium at all.

Thus making the radiation method of heat transfer as the only method out of the three methods which does not require the material medium for the transfer of heat energy.

4 0

2 years ago

Design circuits that demonstrate all of the principles listed below. Set up the circuits and take measurements to show that the

Nata [24]

<u>Explanation</u>:

For series

$\Delta V=V_{1}+V_{2}+\ldots+V_{n}=I R_{1}+I R_{2}+\ldots+I R_{n}(\text {voltages add to the batter } y)$