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3 years ago

How does fouling affects the performance of a heat exchanger?

Engineering

1 answer:

Kisachek [45]3 years ago

6 0

Answer:

Fouling :

When rust or undesired material deposit in the surface of heat exchanger,is called fouling of heat exchanger.

Effect of heat exchanger are as follows"

1.It decreases the heat transfer.

2.It increases the thermal resistance.

3.It decreases the overall heat transfer coefficient.

4.It leads to increase in pressure drop.

5.It increases the possibility of corrosion.

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You’ve experienced convection cooling if you’ve ever extended your hand out the window of a moving vehicle or into a flowing wat

Anna35 [415]

Answer:

Condition A

Heat flux is 1400 W/M^2

Condition B

Heat flux is 12800 w/m^2

Explanation:

Given that:

$T_s$ is given as 30 degree celcius

condition A

Air temperature = - 5 degree c

convection coefficient h = 40 w/m^2. k

$heat\ flux = \frac{Q}{a}= h\Delta = 40{30 - (-5)} = 1400 w/m^2$

condition A

water temperature = 10 degree c

convection coefficient = 800 w/m^2.k

$heat\ flux = \frac{Q}{A} = H(\Delta} = 800\times (30-14) = 12800w/m^2$

7 0

3 years ago

The Ethernet (CSMA/CD) alternates between contention intervals and successful transmissions. Assume a 100 Mbps Ethernet over 1 k

Vesnalui [34]

<h3><u>CSMA/CD Protocol: </u></h3>

Carrier sensing can transmit the data at anytime only the condition is before sending the data sense carrier if the carrier is free then send the data.

But the problem is the standing at one end of channel, we can’t send the entire carrier. Because of this 2 stations can transmit the data (use the channel) at the same time resulting in collisions.

There are no acknowledgement to detect collisions, It's stations responsibility to detect whether its data is falling into collisions or not.

<u>Example: </u>

$T_{P}=1 H r$ , at time t = 10.00 AM, A starts, 10:59:59 AM B starts at time 11:00 AM collision starts.

12:00 AM A will see collisions

Pocket Size to detect the collision.

$\begin{aligned}&T_{t} \geq 2 T_{P}\\&\frac{L}{B} \geq 2 T_{P}\\&L \geq 2 \times T_{P} \times B\end{aligned}$

CSMA/CD is widely used in Ethernet.

<u>Efficiency of CSMA/CD:</u>

In the previous example we have seen that in worst case $2 T_{P}$ time require to detect a collision.

There could be many collisions may happen before a successful completion of transmission of a packet.

We are given number of collisions (contentions slots)=4.

$\text { Propagation day }=\frac{\text {distance}}{\text {speed}}$

Distance = 1km = 1000m

$\begin{aligned}&\text { Speed }=2 \times 10^{8} \mathrm{m} / \mathrm{sec}\\ &T_{P}=\frac{1000}{2 \times 10^{8}}=(0.5) \times 10^{-5}=5 \times 10^{-6}\\ &T_{t}=5 \mu \mathrm{sec}\end{aligned}$

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3 years ago

Discuss the applications of numerical weather forecasting

olchik [2.2K]

Numerical weather prediction (NWP) uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. Though first attempted in the 1920s, it was not until the advent of computer simulation in the 1950s that numerical weather predictions produced realistic results. A number of global and regional forecast models are run in different countries worldwide, using current weather observations relayed from radiosondes, weather satellites and other observing systems as inputs.

3 0

3 years ago

malott, m. e. (2003). paradox of organizational change: engineering organizations with behavioral systems analysis.

mylen [45]

Answer:

Paradox of Organizational Change: Engineering Organizations with Behavioral Systems Analysis. by. Maria E. Malott.

7 0

2 years ago

214Bi83 --> 214Po84 + eBismuth-214 undergoes first-order radioactive decay to polonium-214 by the release of a beta particle,

Zolol [24]

Answer:

Explanation:

Radioactive materials will usually decay based on their specific half lives. In radioactivity, the plot of the natural logarithm of the original radioactive material against time will give a straight-line curve. This is mostly used to estimate the decay constant that is equivalent to the negative of the slope. Thus, the answer is option C.

3 0

3 years ago

Read 2 more answers