Answer:
(a) the reversible power output of turbine is 5810 kw
(b) The second-law efficiency of he turbine = 86.05%
Explanation:
In state 1: the steam has a pressure of 6 MPa and 600°C. Obtain the enthalpy and entropy at this state.
h1 = 3658 kJ/kg s1=7.167 kJ/kgK
In state 2: the steam has a pressure of 50 kPa and 100°C. Obtain the enthalpy and entropy at this state
h2 = 2682kl/kg S2= 7.694 kJ/kg
Assuming that the energy balance equation given
Wout=m [h1-h2+(v1²-v2²) /2]
Let
W =5 MW
V1= 80 m/s V2= 140 m/s
h1 = 3658kJ/kg h2 = 2682 kJ/kg
∴5 MW x1000 kW/ 1 MW =m [(3658-2682)+ ((80m/s)²-(140m/s)²)/2](1N /1kg m/ s²) *(1KJ/1000 Nm)
m = 5.158kg/s
Consider the energy balance equation given
Wrev,out =Wout-mT0(s1-s2)
Substitute Wout =5 MW m = 5.158kg/s 7
s1= 7.167 kJ/kg-K s2= 7.694kJ/kg-K and 25°C .
Wrev,out=(5 MW x 1000 kW /1 MW) -5.158x(273+25) Kx(7.167-7.694)
= 5810 kW
(a) Therefore, the reversible power output of turbine is 5810 kw.
The given values of quantities were substituted and the reversible power output are calculated.
(b) Calculating the second law efficiency of the turbine:
η=Wout/W rev,out
Let Wout = 5 MW and Wrev,out = 5810 kW
η=(5 MW x 1000 kW)/(1 MW *5810)
η= 86.05%
Explain the 11 sections that a typical bill of quantity is divided into
Answer:
The main sections included in the bill of quantities are Form of Tender, Information, Requirements, Pricing schedule, Provisional sums, and Day works.
A steam turbine generator unit is used to produce electricity, where steam enters the turbine with a velocity of 30 m/s and enthalpy (internal energy) of 3348 kJ/kg. The 1 steam leaves the turbine as a mixture of vapor and liquid having a velocity of 60 m/s and an enthalpy of 2550 kJ/kg. The flow through the turbine is adiabatic, and changes in elevation are negligible. Determine the work output from the turbine, if the mass flow rate is 5kg/s.
Answer:
3.983 MW
Explanation:
Given that:
At the inlet:
Velocity (v₁) = 30 m/s
Enthalpy (h₁) = 3348 kJ/kg
At the outlet:
Velocity (v₂) = 60 m/s
Enthalpy (h₂) = 2550 kJ/kg
Mass flow rate (m) = m₁ = m₂ = 5kg/s
According to the steady flow energy equation:
[tex]Q+ m_1 (h_1 + \dfrac{v_1^2}{2000}+ \dfrac{gz_1}{1000} )= m_2(h_2+\dfrac{v_2^2}{2000}+\dfrac{gz_2}{1000})+W_{shaft}[/tex]
Since the elevation (z) is negligible and flow via the turbine is adiabatic:
Then,
Q = 0 and z₁ = z₂
∴
[tex]W_{shaft} = (mh_1-mh_2) + (\dfrac{mv_1^2-mv_2^2}{2000})[/tex]
[tex]W_{shaft} = ((5*3348) -(5*2550)) + (\dfrac{(5*(30)^2)-(5*(60)^2)}{2000})[/tex]
[tex]W_{shaft} = (16740-12750) + (\dfrac{4500-18000}{2000})[/tex]
[tex]W_{shaft} = (16740-12750) + (-6.75)[/tex]
[tex]W_{shaft} = 3983.25 \ kW[/tex]
[tex]\mathbf{W_{shaft} = 3.983 \ MW}[/tex]
Work to be performed can come from the work package level of the work breakdown structure as well as other sources. Which of these is NOT a source of authorized work to be performed?
a. Scope creep
b. Defect repairs
c. Preventive actions
d. Corrective actions
A project is meant to achieve clearly defined goals within present constraints
The correct option for the source of work in a project which is NOT a source of authorized work to be performed is option (a)
a. Scope creep
The reason for the selecting the above option is as follows;
In project management, alongside work planned in a work package, authorized work to be performed can come from;
The repairing of defects found in completed work and which is a requirement for the project to be approvePreventive actions, that are meant to mitigate factors that affect the project timeline and costCorrective actions which include actions meant to rectify parts of the project that produce an error outcomeA scope creep, however, is generally is due to the inclusion of the end
users of the project at a time that is behind schedule, insufficient analysis of
the requirements, and project complexity underestimation. and consists of
changes made after a project has commenced
A scope creep therefore, changes the amount of work to be done which
therefore alters the project timeline, and due to project, budgetary, and
end user constraints, CANNOT be a source of authorized work to be
performed
The correct option for the source that is NOT a authorized work to be performed is option a. Scope creep
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Magnetic particle testing can be done only on metals that can be magnetized.
True or false
if a person is injured at the hospital during a natural disaster a correct action to take is
what does mean setbacks with MRT station?
A technician wants to implement a dual factor authentication system that will enable the organization to authorize access to sensitive systems on a need-to-know basis. What should be implemented during the authorization stage?
Answer: Biometrics
Explanation:
Dual factor authentication refers to an electronic authentication method whereby a user will only be granted an access to an application or a website after the user has successfully been able to present two pieces of evidence which then grants access to the application or website.
Since the technician wants to implement a dual factor authentication system, the biometrics should be implemented during the authorization stage.
Biometrics refers to the body measurements and the calculations that are related to the characteristics of humans. Biometric authentication is used as a form of identification.
Cho biết tác dụng chung của các hệ giằng khung ngang nhà công nghiệp nhẹ 1 tầng 1 nhịp.
2 Air enters the compressor of a cold air-standard Brayton cycle at 100 kPa, 300 K, with a mass flow rate of 6 kg/s. The compressor pressure ratio is 10, and the turbine inlet temperature is 1400 K. The turbine and compressor each have isentropic efficiencies of 80%. For k 5 1.4, calculate (a) the thermal efficiency of the cycle. (b) the back work ratio. (c) the net power developed, in kW. (d) the rates of exergy destruction in the compressor and turbine, respectively, each in kW, for T0 5 300 K.
anxiety: a. is never normal. b. is common of many psychological disorders c. is identical to fear d. is a modern development, unlikely to have roots in human history
Answer:
B
Explanation:
Anxiety is very common especially nowadays but it's especially common in psychological disorders
The impeller shaft of a fluid agitator transmits 20 kW at 430 rpm. If the allowable shear stress in the impeller shaft must be limited to 65 MPa, determine (a) the minimum diameter required for a solid impeller shaft. (b) the maximum inside diameter permitted for a hollow impeller shaft if the outside diameter is 36 mm. (c) the percent savings in weight realized if the hollow shaft is used instead of the solid shaft. (Hint: The weight of a shaft is proportional to its cross-sectional area.)
Given :
Power, P = 20 kW
Speed, N = 430 rpm
Allowable shear stress, τ = 65 MPa
Torque in the shaft is given by :
[tex]$P=\frac{2 \pi NT}{60}$[/tex]
[tex]$T=\frac{60 \times 20 \times 10^3}{2 \pi \times 430}$[/tex]
T = 444.37 N.m
Diameter of the solid shaft is
[tex]$d=\sqrt[3]{\frac{16 T}{\pi \tau}}[/tex]
[tex]$d=\sqrt[3]{\frac{16 \times 444.37}{3.14 \times 65}}[/tex]
[tex]$d=\sqrt[3]{34.83} $[/tex]
d = 3.265 m
d = 326.5 mm
Internal diameter of the hollow shaft is :
[tex]$\frac{T}{\frac{\pi}{32} \left( d_0^4 - d_i^4 \right)}=\frac{\tau}{d_0/2}$[/tex]
[tex]$\frac{444.37}{\frac{3.14}{32} \left( 0.036^4 - d_i^4 \right)}=\frac{65 \times 10^6}{0.036/2}$[/tex]
[tex]$\frac{444.37}{0.09 \left( 1.6 \times 10^{-6} - d_i^4 \right)}=\frac{65 \times 10^6}{0.018}$[/tex]
[tex]$\frac{7.99}{ \left( 1.6 \times 10^{-6} - d_i^4 \right)}=5850000$[/tex]
[tex]$1.3\times 10^{-6} = 1.6 \times 10^{-6} - d_i^4 \right)}$[/tex]
[tex]$d_i^4=300000$[/tex]
[tex]$d_i = 23.40$[/tex] mm
Percentage savings in the weight is given by :
Percentage saving = [tex]$\frac{W_{solid}-W_{hollow}}{W_{solid}}\times100$[/tex]
[tex]$=\frac{V_{solid}-V_{hollow}}{V_{solid}}\times100$[/tex]
[tex]$=\frac{d^2 - (d_0^2 - d_i^2)}{d^2} \times 100$[/tex]
[tex]$=\frac{(326.5)^2 - (0.036^2 - (32.40)^2)}{(326.5)^2} \times 100$[/tex]
[tex]$=\frac{106602 - \left(1.29 \times 10^{-3} - 1049.76 \right)}{106602} \times 100$[/tex]
[tex]$=\frac{106602 - 1049 }{106602} \times 100$[/tex]
[tex]$=\frac{105553 }{106602} \times 100$[/tex]
= 99.01 %
what is the best book for mechanic of materials?
Answer:
As per my experience Egor Popov is one the best book for mechanics of materials.
Explanation:
hope this helps
Functional and nonfunctional requirements documents are used to _____.
define the financial budget of a system
define the purpose of a system
facilitate communication between the users and a system
help exercise control over the inner workings of the firm.
Answer:
Non-functional requirements when defined and executed well will help to make the system easy to use and enhance the performance
Explanation:
True or false: You can create a network with two computers.
Answer
True
. Bơm kiểu piston tác dụng đơn có áp suất p=0,64 Mpa và lưu lượng Q=3,5 l/s. Xác định tốc độ quay của trục bơm và công suất của bơm nếu biết đường kính piston D=150 mm; bán kính tay quay R=60 mm; hiệu suất thể tích của bơm là 0=0,94; hiệu suất chung của bơm b=0,80.
Answer:
not understand language
A mechanic claims to have developed a car engine that runs on water instead of gasoline. What is your response to this claim?
The claim will be impractical. The reason behind this is provided below throughout the explanation segment.
Inside the same combustion chamber, fresh water can't be pressurized even more than fuel as well as air. Consequently, the cylinder does not burn due to a problem with the compressor.To accomplish the development processes, a machine requires any sort of combustible which might cause combustion as well as create a tremendous quantity of power.
Thus, the idea of using water instead of petroleum appears unworkable throughout traditional engines.
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An incompressible viscous fluid flows through a pipe with a flow rate of 1 mL/s. The pipe has a uniform diameter D0 and a length L0. A pressure difference of P0 between the ends of the pipe is required to maintain the flow rate. What would be the flow rate if the pressure difference was increased to 2P0 and the diameter was increased to 2D0
Answer:
[tex]Q_2 = 32[/tex] mL/s
Explanation:
Given :
The flow is incompressible viscous flow.
The initial flow rate, [tex]Q_1[/tex] = 1 mL/s
Initial diameter, [tex]D_1= D_0[/tex]
Initial length, [tex]L_1=L_0[/tex]
The initial pressure difference to maintain the flow, [tex]P_1=P_0[/tex]
We know for a viscous flow,
[tex]$\Delta P = \frac{32 \mu V L}{D^2}$[/tex]
[tex]$\Delta P = \frac{32 \mu Q L}{\frac{\pi}{4}D^4}$[/tex]
[tex]$Q \propto \Delta P \times D^4$[/tex]
[tex]$\frac{Q_1}{Q_2}= \frac{P_1}{P_2} \times \left( \frac{D_1}{D_2} \right)^4$[/tex]
[tex]$\frac{1}{Q_2}= \frac{P_0}{2P_0} \times \left( \frac{D_0}{2D_0} \right)^4$[/tex]
[tex]$\frac{1}{Q_2}= \frac{1}{2} \times \left( \frac{1}{2} \right)^4$[/tex]
[tex]$\frac{1}{Q_2}= \frac{1}{32}$[/tex]
∴ [tex]Q_2 = 32[/tex] mL/s
The flow rate if the pressure difference was increased to 2P0 and the diameter was increased to 2D0 is; Q2 = 32 mL/s
We are given;
Initial flow rate; Q1 = 1 mL/s
Initial uniform diameter; D0
Initial Length; L0
Initial Pressure difference; P0
Relationship between pressure, flow rate and diameter for vicious flow is given by;
Q1/Q2 = (P1/P2) × (D1/D2)⁴
Where;
Q1 is initial flow rate
Q2 is final flow rate
P1 is initial pressure difference
P2 is final pressure difference
D1 is initial diameter
D2 is final diameter
We are told that the pressure difference was increased to 2P0 and the diameter was increased to 2D0. Thus;
P2 = 2P0
D2 = 2D0
Thus;
1/Q2 = (P0/2P0) × (D0/2D0)⁴
>> 1/Q2 = ½ × (½)⁴
1/Q2 = 1/32
Q2 = 32 mL/s
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You are given a pot of hot tea (350 mL) at a temperature of 85°C and a quantity of ice at -12°C. Determine the absolute minimum amount of ice you can add to the hot tea so that at equilibrium you have iced tea (ie. a very, very small amount of ice and some water). You can assume tea has the same density (1.00 g/mL) and specific heat (4190 J/kgK) as liquid water. The heat of fusion of H2O is 3.33x10^5 J/kg. The specific heat of ice is 2090 J/kgK.
Answer:
348 g
Explanation:
The heat gained by the ice equals the heat lost by the hot tea.
Also, since we require a very, very small amount of ice and some water, to still have some ice, the temperature of the hot tea has to decrease to the melting point of ice which is 0°C. So, the final temperature of the mixture is 0 °C.
So, mc(T - T') + mL = -MC(T - T") where m = mass of ice, c = specific heat of ice = 2090 J/kgK., T = final temperature of mixture = 0 °C, T' = initial temperature of ice = -12 °C, L = heat of fusion of H2O = 3.33 × 10⁵ J/kg, M = mass of hot tea = ρV where ρ = density of tea = 1.00 g/mL and V = volume of hot tea = 350 mL. So, M = ρV = 1.00 g/mL × 350 mL = 350 g = 0.350 kg, C = specific heat of tea = 4190 J/kgK and T" = initial temperature of tea = 85 °C.
Making m subject of the formula, we have
mc(T - T') + mL = -MC(T - T")
m[c(T - T') + L] = -MC(T - T")
m = -MC(T - T")/[c(T - T') + L]
substituting the values of the variables into the equation, we have
m = -MC(T - T")/[c(T - T') + L]
m = -0.350 kg × 4190 J/kgK(0 °C - 85 °C.)/[2090 J/kgK(0 °C. - (-12 °C)) + 3.33 × 10⁵ J/kg]
m = -1466.5 J/kK(- 85 °C)/[2090 J/kgK(0 °C + 12 °C)) + 3.33 × 10⁵ J/kg]
m = 124652.5 J/[2090 J/kgK(12 °C) + 3.33 × 10⁵ J/kg]
m = 124652.5 J/[25080 J/kg + 3.33 × 10⁵ J/kg]
m = 124652.5 J/358080 J/kg
m = 0.3481 kg
m = 348.1 g
m ≅ 348 g
So, the minimum amount of ice to be added is 348 g.
an atom that gained an electron is called
Answer:
Hey mate......
Explanation:
This is ur answer.....
When an atom gains/loses an electron, the atom becomes charged, and is called an ion.Hope it helps!
Brainliest pls!
Follow me :)
A 2-stage dcv that has an internal pilot does not work well (if at all) on
Answer:
i really font onow why tbh eot you
A O.1m³ rigid tank contains steam initially as 500k pa and 200°C. The steam is now allowed to cool until the temperature drops to 50°C. Determine the amount of heat transfer during the process and the final pressure in the tank
Answer:
Check it out here
Explanation:
Which of the following conditions were present in over 80% of paddling fatalities from 1995-2000?
Answer:
80% of the people that were killed weren't wearing a safety flotation device ( in correct terminology Personal Flotation Device, or PFD )
Explanation:
Hence they drowned due to the lack of safety.
The condition present in over 80% of paddling fatalities is that the victims were said to be not wearing a personal flotation device (PFD).
What is paddling in the sea?The act of paddling is known to be a sport or something one can do for fun or for games.
Conclusively, a lot of paddling fatalities 1995-2000 was due to the fact that the people who were engage in the sport or act were not putting on a personal flotation device (PFD) and this can lead to death or drowning.
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Rafel knows that lessons learned is a valuable aid to future projects. When should he and his team address
lessons learned on a project?
Select an answer:
Add lessons learned as a topic in status meetings
Review past lessons learned so a new one does not have to be created,
Create lessons learned at the end of the project.
Brainstorm lessons learned at the beginning of a project
Answer: Create lessons learned at the end of the project.
Explanation:
Lessons learned are the experiences that are gotten from a project which should be taken into account for the future projects. Lesson learned are created at the end of the project.
The main objective of the lessons learned is that they show both the positive experience and the negative experience of a project and this will help the future projects that will be undertaken.
hỗ trợ mình với được không các bạn
Answer:
Explanation:
Be bop
A resistor has code 104 printed on it .What is the resistive value of this resistor
Answer:
X = 1 (1st digit in the code)
Y = 0 (2nd digit)
Z = 4 (3rd multiplier digit)
104 → 10 × 10^4 Ω
→ 10 × 10000Ω
→ 100 kΩ
resistors are marked 104, 105, 205, 751, and 754. The resistor marked with 104 should be 100kΩ (10x10^4), 105 would be 1MΩ (10x10^5), and 205 is 2MΩ (20x10^5). 751 is 750Ω (75x10^1), and 754 is 750kΩ (75x10^4).
Here we need to understand how a code in a resistor gives us information on the resistor. Here we will see that the code means that the resistance is 100,000 Ω.
When we use numbers, let's assume that we have 3 single-digit numbers abc.
So if the code in our resistor is abc, this will mean that the resistance of the resistor is:
ab×10^c Ω
Using this general rule we can see that if the code is 104, then the resistance will be:
r = 10×10^4 Ω
= 100,000 Ω
Then we can conclude that the resistive value of this resistor is 100,000 Ω
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Tech A says that when performing a cylinder leakage test, the piston should be positioned at bottom dead center. Tech B says that a blown head gasket would generally leak past the exhaust valve. Who is correct
The causes of low compression in an engine cylinder and leakage past the exhaust can be identified by performing mechanical tests on the engine
The correct technician is Tech B; Blown head gasket would generally leak past the exhaust valve
The reason for arriving at the above selection is as follows:
A cylinder leakage test is generally performed after there is an indication of low compression from one or more cylinders. The test allows the identification of the part of the cylinder that is leaking.
The cylinder that shows sign of low compression is often the location that the cylinder leakage test is performed, although, the test can be performed on every cylinder
A cylinder leakage test is valid only when
The temperature of engine is about the temperature range of the engine in operationThe cylinder under test is at the Top Dead Center (TDC) position, such that the position of the piston in the cylinder is at the top or highest point of its strokeTherefore, the positioning of the piston in the bottom dead center during a leakage test as mentioned by Tech A is not correct
The route of coolant in the engine are sealed by the cylinder head gasket, where there is a blown head gasket, the coolant will be allowed to leak into the cylinders and into the exhaust, causing white smoke and sweet odor of antifreeze
Therefore, Tech B is correct, coolant leakage into the exhaust is an indication of a blown head gasket
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Why is logging done during drilling?
Answer:
Logging while drilling (LWD) is a technique of conveying well logging tools into the well borehole downhole as part of the bottom hole assembly (BHA). ... In these situations, the LWD measurement ensures that some measurement of the subsurface is captured in the event that wireline operations are not possible
which type of clectrical circuit is represented by this diagram?
Answer:
parallel
Explanation:
All components in this circuit are tied in parallel. Each component experiences the same voltage from one terminal to the other. It is a parallel circuit.
beacuse thye want them to hav egoood and thye wn thme tto
Answer:
I don't understand the question
how to solve circuit theory using mesh analysis
Explanation:
Find a minimal set of cycles that covers all vertices and edges of the circuit graph. For each cycle, define a "mesh" current, and write the Kirchhoff's Voltage Law (KVL) equation with respect to each of the edges in the cycle. Where an edge is part of more than one cycle, all current(s) defined for the edge will contribute to the voltage there.
This will give as many equations as there are mesh currents. Solve the resulting system of equations. The (signed) sum of the mesh currents through any edge is the current in that circuit branch.
__
Example
Consider the attached circuit. It shows mesh currents I1, I2, and I3 in graph cycles with those numbers. The KVL equations are ...
mesh 1: I1(R3 +R2 +R1) -I2·R1 -I3·R2 = Vi (the voltage across the current source)
mesh 2: -I1·R1 +I2(r1 +1/(sC)) -I3(1/(sC)) = Vs
mesh 3: -I1·R2 -I2(1/(sC)) +I3(R2 +sL +1/(sC)) = 0
You will note that the matrix of equation coefficients is symmetric.
__
In this example, you will end with I1 as a function of Vi. If I1 is a given source value, that relation can be used to find Vi.
