The ultimate BOD of a river just below a sewage outfall is 50.0 mg/L, and the oxygen deficit at the outfall D0 is 2.0 mg/L. The
saturation value of dissolved oxygen is 11.0 mg/L. The deoxygenation rate coefficient kd is 0.30/day, and the reaeration rate coefficient kr is 0.90/day. The river is flowing at the speed of 45.0 miles per day. The only source of BOD on this river is this single outfall.
A. Find the critical distance downstream at which DO is a minimum.
B. Find the minimum O.
A. Find the critical distance downstream at which DO is a minimum.
B. Find the minimum O.
1 answer:
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Answer:
a)temperature=69.1C
b)3054Kw
Explanation:
Hello!
To solve this problem follow the steps below, the complete procedure is in the attached image
1. draw a complete outline of the problem
2. to find the temperature at the turbine exit use termodinamic tables to find the saturation temperature at 30kPa
note=Through laboratory tests, thermodynamic tables were developed, these allow to know all the thermodynamic properties of a substance (entropy, enthalpy, pressure, specific volume, internal energy etc ..)
through prior knowledge of two other properties such as pressure and temperature.
3. Using thermodynamic tables find the enthalpy and entropy at the turbine inlet, then find the ideal enthalpy using the entropy of state 1 and the outlet pressure = 30kPa
4. The efficiency of the turbine is defined as the ratio between the real power and the ideal power, with this we find the real enthalpy.
Note: Remember that for a turbine with a single input and output, the power is calculated as the product of the mass flow and the difference in enthalpies.
5. Find the real power of the turbine
ANSWERS:
Explanation:
Given:
Piston cylinder assembly which mean that the process is constant pressure process P=C.
<u>AMMONIA </u>
state(1)
saturated vapor
The temperature
Isothermal process
a)
( double)
b)
(reduced by half)
To find the final state by giving the quality in lbf/in we assume the friction is neglected and the system is in equilibrium.
state(1)
using PVT data for saturated ammonia
then the state exists in the supper heated region.
a) from standard data
assume linear interpolation
b)
from standard data
then the state exist in the wet zone
