Answer:
When the uneven burning of the fuel takes place due to the incorrect air/fuel mixture inside the engine cylinder, a knocking sound is observed. This is called as the engine knocking.
Explanation:
When the uneven burning of the fuel takes place due to the incorrect air/fuel mixture inside the engine cylinder, a knocking sound is observed. This is called as the engine knocking.
The engine knock problem can be caused due to the following reason
a) When the octane rating of the fuel used is low.
b) The deposition of the carbon around the cylinder walls takes place.
c) The spark plug used in the vehicle is not correct.
Solution :
The isentropic efficiency of the turbine is given as :



The entropy relation for the isentropic process is given by :




Now obtaining the properties from the ideal gas properties of air table :
At 


Calculating the relative pressure at state 2s :



Obtaining the properties from Ideal gas properties of air table :
At
, 
Considering the isentropic relation to calculate the actual temperature at the turbine exit, we get:





So, at
, 
Now calculating the work developed per kg of air is :

= 1757.57 - 975.66
= 781 kJ/kg
Therefore, the temperature at the exit is 938 K and work developed is 781 kJ/kg.
Answer:
The answer is 27.69 [psi]
Explanation:
(Barinly´s editor seem to not be working properly so please see attachment)
We know that:
Where:
- σ => Stress in the material
- Pin => Internal Pressure
- Din => Internal diameter
- t => Thickness
Since we know that thre Stress is directly proportional to Pin and Din but inversely proportional to thickness, we need to add a proportionality constant "k" to our equation to make it complete:
We also know that the Stress is 100 [psi] when Pin is 25 [psi], Din is 5 [in] and thickness is .75 [in], using this values we can solve for k:
thus k = .6
Now all we need to know is use the same equation but using the new parameters: Pin = 15 [psi], Din = 2 [in] and t= .65 [in]
The stress is 27.69 [psi]