Answer:
The correct option is (e) η = 0.66
Explanation:
given data:
temperature at entry is 627 degree C
temperature at exit is 27 degree C
the efficiency of a engine is given as η
where is temperature in kelvin at exit point
is temperature in kelvin at entry point
η = 66.66 %
Answer:
W=-260.66 kJ (negative answer means, that the work was done on the gas)
Explanation:
1) Convert temperature from C to K- T=24+273=297K- all temperature in the gas problems should be used in Kelvins;
2) We need to analyse type of the process- it is given, that the temperature is constant, so it is an Isothermal process, which means, that the equation of the process is: pV=const (constant);
3) Work, done on the system, should be calculated using the following equation:
4) To calculate initical and final volumes (Va and Vb), we can use the following equation: pV=mRT, so V=mRT/p. Note, that the pressure is changing, thus we can calculate volumes for the both cases- initial and final, using initial (120kPa) and final (600kPa) pressures, in addition, we can find equation for the pressure, as function of the volume, which we need to use for the integration in step 3: p=mRT/V;
5) Now we can calculate the integral, given in the step 3: . As we have pressure as a known values, we can re-write the equation, using pressures:
Note, that natural logarithm (ln) yields negative answer, which supports the question, that the work was done on the gas, not by the gas.
Answer:
The settling velocity of the particles (Vs) is greater than the overflow rate (V₀), thus the particles will settle out and will be removed.
Explanation:
Given;
volumetric flow rate of the treatment, Q₀ = 12,000 m³/day
length of the rectangular tank, L = 25 m
width of the tank, W = 12 m
height of the tank, H = 3 m
settling velocity of the particles, = 6 x 10⁻³ m/s
The overflow rate of the sediments are calculated as follows;
where;
As is the surface area of the tank, m²
Q₀ is the flow rate, m³/s
As = 2LW + 2LH + 2WH
As = (2 x 25 x 12) + (2 x 25 x 3) + (2 x 12 x 3)
As = 822 m²
The overflow rate;
The settling velocity of the particles (Vs) is greater than the overflow rate (V₀), thus the particles will settle out and will be removed.