Consider a circular tube of diameter D and length L, with a mass flow rate of m_dot. (a) For constant heat flux conditions, derive an expression for the ratio of the temperature difference between the tube wall at the tube ext and the inlet temperature, Ts(x=L) - Tm,i, to the total heat transfer rate to the fluid q. Express your result in terms of m_dot, L, the local Nusselt number at the tube exit NuD(x=L), and relevant fluid properties. (b) Repeat part (a) for constant surface temperature conditions. Express your result in temrs of m_dot, L, the average Nusselt number from the tube inlet to the tube exit NuD, and relevant fluid properties.
Answers
(a) For constant heat flux conditions, the expression for the ratio of the temperature difference between the tube wall at the tube exit (Ts(x=L)) and the inlet temperature (Tm,i) to the total heat transfer rate to the fluid (q) can be derived using the following steps:
1. Apply the energy balance equation to the tube segment of length L:
q = m_dot * Cp * (Ts(x=L) - Tm,i)
where q is the total heat transfer rate, m_dot is the mass flow rate, Cp is the specific heat capacity of the fluid, Ts(x=L) is the temperature at the tube exit, and Tm,i is the inlet temperature.
2. Substitute the heat transfer rate with the Nusselt number:
q = NuD(x=L) * k * A * (Ts(x=L) - Tm,i) / L
where NuD(x=L) is the local Nusselt number at the tube exit, k is the thermal conductivity of the fluid, and A is the cross-sectional area of the tube.
3. Rearrange the equation to solve for the desired ratio:
(Ts(x=L) - Tm,i) / q = L / (NuD(x=L) * k * A)
The right-hand side of the equation represents the thermal resistance of the tube.
Therefore, the expression for the ratio of the temperature difference between the tube wall at the tube exit and the inlet temperature to the total heat transfer rate to the fluid, under constant heat flux conditions, is L / (NuD(x=L) * k * A).
(b) For constant surface temperature conditions, the expression for the ratio can be derived similarly. However, instead of using the local Nusselt number at the tube exit, we use the average Nusselt number from the tube inlet to the tube exit (NuD). The expression becomes:
(Ts(x=L) - Tm,i) / q = L / (NuD * k * A)
The only difference is the use of the average Nusselt number (NuD) instead of the local Nusselt number (NuD(x=L)).
Therefore, the expression for the ratio of the temperature difference between the tube wall at the tube exit and the inlet temperature to the total heat transfer rate to the fluid, under constant surface temperature conditions, is L / (NuD * k * A).
Learn more about thermal conductivity here:
https://brainly.com/question/14919402
#SPJ11
Related Questions
a spring with spring constant 60 N/m has 480 J of EPE stored in it. How much is compressed?
Answers
Answer:
Below
Explanation:
Use formula for EPE :
EPE = 1/2 k x^2
480 j = 1/2 (60 N/m) x^2 shows x = 4 meters
A piston-cylinder device initially contains 15 ft3 of helium gas at 25 psia and 70°F. Helium is now compressed in a polytropic process (PVconstant) to 70 psia and 300°F. Determine a. The entropy change of helinn (5%) b. The entropy change of the surroundings [5%] c. Whether this process is reversible, irreversible, or impossible. (3%) Assume the surroundings are at 70°F
Answers
The entropy change of the surroundings can be assumed to be negligible if we consider an adiabatic process with no heat exchange.
To determine the entropy change of helium and the surroundings, we need to apply the principles of thermodynamics. Let's break down the problem into parts:
a. The entropy change of helium (ΔS_helium):
To calculate the entropy change of helium gas, we can use the ideal gas equation and the definition of entropy change:
ΔS_helium = C_p * ln(T2/T1) - R * ln(V2/V1)
First, we need to determine the final volume, V2. Since the process is polytropic (PV constant), we can use the relationship:
P1 * V1^n = P2 * V2^n
where n is the polytropic exponent. In this case, since it's a polytropic process, n is not specified. Therefore, we need to know the value of n or find a way to determine it.
Unfortunately, without the value of the polytropic exponent, we cannot calculate the entropy change of helium (ΔS_helium). The polytropic exponent is essential to determine the relationship between pressure and volume during the process.
b. The entropy change of the surroundings (ΔS_surroundings):
The entropy change of the surroundings can be determined based on the heat transfer during the process. If we assume that the process is adiabatic (no heat transfer with the surroundings) and the surroundings are at a constant temperature of 70°F, then the entropy change of the surroundings would be zero (ΔS_surroundings = 0). In this case, there is no heat exchange with the surroundings, so the entropy change of the surroundings is negligible.
c. Reversibility of the process:
Without knowing the polytropic exponent or more information about the process, we cannot definitively determine if the process is reversible, irreversible, or impossible. The polytropic exponent would provide insights into the nature of the process and its reversibility.
To learn more about entropy
https://brainly.com/question/20166134
#SPJ4
Which describes the innermost layer of Earth?
Answers
Answer and Explanation:Option A->The innermost layer of the earth is known as the core. It is divided into inner core and outer core. It comprises of a high concentration of nickel and iron.
Convert 11011 into binary number to decimal number
Answers
Answer: The binary number 11011 is 27 as a decimal number
Explanation:
The electric field between the plates of an ideal parallel plate capacitor has magnitude 3000 v/m. the change in potential energy of the system as a 2 c charge is moved from a to b is ______ j.
Answers
If the distance between the plates is 1 meter, the change in potential energy of a 2 C charge moved from point A to point B would be 6000 Joules. The change in potential energy of a 2 C charge as it is moved from point A to point B in an ideal parallel plate capacitor can be calculated using the formula of Potential voltage.
Formula of potential voltage is given below:
ΔPE = q * ΔV
where ΔPE is the change in potential energy, q is the charge, and ΔV is the change in potential voltage.
Given that the electric field between the plates of the capacitor has a magnitude of 3000 V/m, we can calculate the potential voltage difference using the formula:
ΔV = E * d
where E is the electric field and d is the distance between the plates.
Since the problem does not provide the value of d, we cannot calculate the exact potential voltage difference or the change in potential energy. However, we can provide a general example to illustrate the calculation.
Let's assume the distance between the plates, d, is 1 meter. In this case, the potential voltage difference, ΔV, would be:
ΔV = 3000 V/m * 1 m = 3000 V
Substituting this value into the first formula, we can calculate the change in potential energy:
ΔPE = 2 C * 3000 V = 6000 J
Therefore, if the distance between the plates is 1 meter, the change in potential energy of a 2 C charge moved from point A to point B would be 6000 Joules.
To know more about capacitor
https://brainly.com/question/30529897
#SPJ11
All large astronomical telescopes are reflectors becausea. chromatic aberration is minimized.
b. they are not as heavy as refracting telescopes.
c. they can be shorter than refracting telescopes.
d. all of the above
Answers
All large astronomical telescopes are reflectors because they offer better image quality, can be built to larger sizes, and are easier to handle and transport than refracting telescopes. The correct answer is (d) all of the above.
All large astronomical telescopes are reflectors because they offer several advantages over refracting telescopes:
a. Chromatic aberration is minimized: In a refracting telescope, different colors of light refract at slightly different angles, which causes chromatic aberration or color distortion. Reflecting telescopes do not suffer from this problem because they use mirrors instead of lenses to gather and focus light.
b. They are not as heavy as refracting telescopes: The lenses used in refracting telescopes can be very heavy and are prone to distortion, which can limit their size. Reflecting telescopes, on the other hand, use lightweight mirrors, which can be much larger and are less prone to distortion.
c. They can be shorter than refracting telescopes: The light path in a reflecting telescope is folded, allowing the tube to be shorter than a refracting telescope of the same focal length. This makes reflecting telescopes easier to mount and transport.
Therefore, all large astronomical telescopes are reflectors because they offer better image quality, can be built to larger sizes, and are easier to handle and transport than refracting telescopes.
for such more question on telescopes
https://brainly.com/question/30051913
#SPJ4
HELP DUE IN AN HOUR!! said last answer choice was incorrect.
Answers
Calculate the total work done (J) by a force given by: F = ( 3i
-6j) N to move an object a displacement given by: R = ( 8i +
6k) m
O a
- 12
Rb
18 i-48)
C C
C
24i - 36j
O d.
d
+ 24
Answers
Work done (J) by the force is 60i - 78j + 18k.
Given,
F = (3i - 6j) NR
= (8i + 6k) m – 12i – 18j + 24J
= F * dJ = (3i - 6j) * (8i + 6k – 12i – 18j + 24)J
= (3i - 6j) * (-4i - 18j + 6k + 24)J
= (-12i - 54j + 18k + 72i - 24j)J
= (60i - 78j + 18k)J
Work done (J) by the force is 60i - 78j + 18k.
learn more about force here
https://brainly.com/question/12785175
#SPJ11
2) Ariel dropped a golf ball from her second story window. The ball starts from rest and hits the sidewalk 1.5 s later with a velocity of 14.7 m/s. Find the average acceleration of the golf ball.1.5x14.7 =22.05
Answers
Answer:
Acceleration = 9.8m/s²
Explanation:
Given the following data;
Initial velocity = 0m/s (since it's starting from rest).
Final velocity, v = 14.7m/s
Time, t = 1.5 seconds.
To find acceleration;
In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.
Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate an object’s acceleration.
Mathematically, acceleration is given by the equation;
\(Acceleration (a) = \frac{final \; velocity - initial \; velocity}{time}\)
\(Acceleration = \frac{v - u}{t}\)
Substituting into the equation, we have;
\(Acceleration = \frac{14.7 - 0}{1.5}\)
\(Acceleration = \frac{14.7}{1.5}\)
Acceleration = 9.8m/s²
Therefore, the average acceleration of the golf ball is 9.8m/s².
Which two options are forms of kinetic energy?
A. Nuclear energy
B. Thermal energy
C. Chemical energy
D. Gravitational energy
E. Sound energy
Answers
Answer:
B. Thermal energy
E. Sound energy
Explanation:
Thermal and sound energy is kinetic energy.
Kinetic energy is the energy that results as a function of the motion of a body or the particles of the medium.
Sound energy is transmitted by the vibration of the particles in the air. The vibration leads to movement of the particles and hence, kinetic energy is produced.
Thermal energy originates as a result of the temperature differences in a body. This temperature difference leads to the increase in the kinetic energy of some particles which also causes vibration and motion of the particles.
The two options which are forms of kinetic energy include:
Thermal energySound energyWhat is Kinetic energy?Kinetic energy is the form of energy possessed by a body by virtue of its
motion.
Thermal energy possesses kinetic energy as a result of the high
temperature bringing about an increase in the collision of the particles.
Sound energy also possesses kinetic energy as a result of the vibrations
through the movement of energy in a medium.
Read more about Kinetic energy here https://brainly.com/question/8101588
As a general rule, women __________.
A. are more flexible than men
B. are less flexible than men
C. are as flexible than men
D. are flexible in different ways than men
Answers
Answer:
a
Explanation:
How long can power be retained in the high voltage system once it has been disabled?
Answers
Power can be retained in the high voltage system for up to two minutes once it has been disabled.
A High voltage carries more than 1000 volts between conductors and 600 volts between conductors and ground.
Safety and Usage of High Voltage Power Supply,High voltage power supplies must be handled with care, and must be covered,Always connect a ground wire,Do not touch high voltage areas,Pay attention to electric charge in cables,Disconnect the input line before touching.Hence, safety should be your priority first when working on high voltages.To learn more about High voltage here
brainly.com/question/13521443
#SPJ4
bakit itinuring angkop na angkop ang mga nilalamab ng ibong adarna sa kalinangan at kulturang pilipino
Answers
Answer:
Itinuring na angkop ang mga nilalaman ng Ibong Adarna sa kalinangan at kulturang Pilipino bagama't sinasabi ng marami na isang halaw o huwad na panitikan lamang ito sapagkat makikita dito ang pananampalataya sa Poong Maykapal, mataas na pagpapahalaga sa kapakanan ng pamilya, paggalang ng anak sa magulang, paggalang sa nakatatanda, pagtulong sa nangangailangan at pagpapakita ng lakas ng loob sa oras ng problemang kinakarap. Upang maunawaan ng lubusan buksan ang: brainly.ph/question/512605 brainly.ph/question/112864 brainly.ph/question/1789641Explanation:
#AnswerForTreesWilbur ran 1-kilometer. Then he ran 500 meters. How many meters did Wilbur run all together?
A) 15,000
B) 1,500
C) 1000
D) 150
Answers
What can Lisa do to increase the strength of the electromagnet? She can use a nail with weaker magnetic properties. She can change the direction of the nail. She can increase the number of wire loops. She can reduce the current in the wire.
Answers
Answer:She can increase the number of wire loops
Explanation: When the number of loops of wire ( usually around the iron ) increases, the strength of the electromagnet is increased.
According to the equation
B=μ₀ N I
Where
μ₀ = permeability of the core
N= Number of turns of the coil
I= Current flowing through the coil
From the equation above , we can see that The strength of an electromagnet depends the amount of current, no of turns of coil and the permeability core of coil. we can now say that Increasing the number of wire loops increases the strength of electromagnet.
Therefore, Lisa should increase the number of wire loops to increase the strength of the electromagnet
Answer:
C
Explanation:
Edge2021
Runner A takes 45 s to run 400 m. Runner B takes 48 s to run the same distance. Which runner has the greater average speed?
Answers
As you leap upward from the ground, how does the force that you exert on the ground compare with your weight?
Answers
Unbeknownst to the students, every time the school floors are waxed, Mr. Tracy, the principal, likes to slide down the Hallway in his socks. Mr. Tracy weighs 85 kg and the coefficient of sliding friction between his socks and the floor is 0.120. What is the force of friction that opposes Mr. Tracy's motion down the hall?
Answers
Answer:
f = 99.96 N
Explanation:
Weight of Mr. Tracy, W = 85 kg
The coefficient of sliding friction between his socks and the floor is 0.12.
We need to find the force of friction that opposes Mr. Tracy's motion down the hall.
The force of friction is given by :
\(f=\mu mg\\\\f=0.12\times 85\times 9.8\\\\f=99.96\ N\)
So, the required force of friction is 99.96 N.
The Appalachian mountain range in the Eastern United States was once much taller than the Rocky mountain range in the Western United States. Currently, however, the Appalachian mountain range is much smaller than the Rocky mountain range
What do you think may have caused this change in height?
Answers
explanation
ik
Answer:
The answer is erosion
Explanation:
I did this before
Which of the following information is necessary to describe an object's motion? position, speed, direction, position, direction, and speed
Answers
Answer:
position speed and direction
Explanation:
hope that helps =)
also i love your profile pic i love fnaf myself!!!!
if h equals 50 km/sec/mpc, then a galaxy with a radial velocity of 50,000 km/sec will have a distance of about 1 mpc.
T/F
Answers
If h equals 50 km/sec/mpc, then a galaxy with a radial velocity of 50,000 km/sec will have a distance of about 1 mpc is false.
The formula used to calculate the distance to a galaxy based on its radial velocity is given by Hubble's Law: v = H0 × d
where v is the radial velocity of the galaxy, H0 is the Hubble constant, and d is the distance to the galaxy.
In this case, the radial velocity is given as 50,000 km/sec, and if we assume the value of the Hubble constant (H0) to be 50 km/sec/Mpc, we can rearrange the equation to solve for the distance:
d = v / H0 = 50,000 km/sec / 50 km/sec/Mpc = 1,000 Mpc
Therefore, a galaxy with a radial velocity of 50,000 km/sec would have a distance of 1,000 Mpc, not 1 Mpc. Hence, the statement is False.
To learn more about radial velocity
https://brainly.com/question/29569575
#SPJ11
Calculate the moment of inertia of a thin rim, with mass m = 10kg, and radius R = 20cm with respect to an axis perpendicular to its plane, which passes through a point on its circumference.
Answers
Given data
*The given mass of thin rim is m = 10 kg
*The given radius of the rim is r = 20 cm = 0.20 m
The formla for the moment of inertia of thin rim with respect to an axis perpendicular to its plane, which passes through a point on its circumference is given as
\(\begin{gathered} I=mr^2+mr^2 \\ =2mr^2 \end{gathered}\)Substitute the known values in the above expression as
\(\begin{gathered} I=2(10)(0.20)^2 \\ =0.8kg.m^2 \end{gathered}\)Hence, the moment of inertia of thin rim with respect to an axis perpendicular to its plane, which passes through a point on its circumference is I = 0.8 kg.m^2
What is the total amount of energy absorbed by the substance as it completely changes from a solid at 40 degrees Celsius to a gas at 200 degrees Celsius?
Please.:(
Answers
The heating curve shows that 12kJ of heat was absorbed.
What is the heating curve?The heating curve is an image that we use to show the relationship between the heat that is applied and the temperature rise of a body. Recall that heat is a form of energy that tends to arise as a result of the temperature rise between the bodies. The heating curve of the object has been attached to this answer.
In order to find the amount of energy absorbed by the substance as it completely changes from a solid at 40 degrees Celsius to a gas at 200 degrees Celsius, we have to look carefully at the heating curve.
We can see from the heating curve that 12kJ of heat was absorbed.
Learn more about heating curve:https://brainly.com/question/10481356
#SPJ1
A car, starting from the origin, travels 4 km east and then 7 km west.
What is the net displacement of the car from the initial point?
04 km east
0 3 km west
7km east
O 7 km west
3 km east
Answers
03 km west
Explanation:
because from east to west it travelled 4km the from west it travelled 4km back to the origin and 3km from origin to west
Which planets are terrestrial? select three options. jupiter mars mercury uranus venus
Answers
Mars, mercury, and venus are the planets that are terrestrial planets.
What is the terrestrial planet?A terrestrial planet is one that is predominantly made up of silicate rocks or metals. The inner planets nearest to the Sun, are Mercury, Venus, Earth, and Mars, as terrestrial planets within the solar system.
Mars, mercury, and venus are the planets closest to the sun.
Hence mars, mercury, and venus are the planets that are terrestrial planets.
To learn more about the terrestrial planet refer to the link;
https://brainly.com/question/18089177
light from an object with a height of 1 cm is sent through a thin lens with a focal length of 10 cm. this light produces an image on a screen that is 50 cm away. what is the distance between the initial object and the lens?
Answers
The distance between the initial object and the lens is 12.5 cm.
The lens equation is used to determine the position and size of an image formed by a lens, given the object distance and focal length. Using the thin lens equation.
1/f = 1/i + 1/o
where f is the focal length of the lens, i is the distance between the lens and the image, and o is the distance between the lens and the object.
Given that f = 10 cm, i = 50 cm, and the height of the object h = 1 cm, we can solve for do as follows:
1/10 = 1/50 + 1/o
1/o = 1/10 - 1/50
1/o = 4/50
1/o = 1/12.5
o = 12.5 cm.
To know more about light, here
brainly.com/question/19426796
#SPJ4
suppose you discover a new cepheid variable star. what steps would you take to determine its distance?.
Answers
The following steps would i take to determine its distance.
What is distance?Distance is defined as the amount of space between two points. It can be measured in several different ways, including kilometers, miles, light-years, and even parsecs. Distance is an important concept in physics, mathematics, and other sciences, as it helps to quantify the size of objects and their relative positions in space. It is also used in everyday life, such as when calculating the time it will take to get from one place to another.
1. Measure the period of the Cepheid variable star.
2. Use the period-luminosity relationship to derive its intrinsic luminosity.
3. Measure its apparent magnitude in the sky.
4. Use the inverse-square law to calculate the distance to the star given its intrinsic luminosity and apparent magnitude.
To know more about distance click-
https://brainly.com/question/26550516
#SPJ4
if a 50 N block is resting on a steel table with a coefficient of static friction
Answers
If F = 37 N, the static frictional force between the block and the table and the minimum force required to move it must be equal.
How is the minimum force of static friction determined?It is the force that regulates itself. The value of static friction varies from zero to the smallest force required to initiate motion. The formula for determining static friction is as follows: Normal Force divided by the static friction coefficient is static friction.
Is weight equivalent to static friction?Although the maximum static friction will rise, the frictional force will always be the same as the weight in mg because friction cannot accelerate an object. Because FrN can take any value less than N to balance the weight, this is the case.
To know more about static frictional visit :-
https://brainly.com/question/13000653
#SPJ1
If a car with a mass of 6,000kg is accelerating at a rate of 8 m/s2 and hits a tree, what force does it have
Answers
Answer:
48,000 NExplanation:
The force acting on an object given it's mass and acceleration can be found by using the formula
force = mass × acceleration
From the question we have
mass = 6,000 kg
acceleration = 8 m/s²
We have
force = 6,000 × 8 = 48,000
We have the final answer as
48,000 NHope this helps you
. Justin completes an experiment length of time a paper airplane stays in flight. He records his results in a
data table. These results are known as _______results.
A. written
B. tabled
C. qualitative
D. quantitative
Answers
Explanation:
Qualitative is to observe and note a quality about something - like the paper airplanes are made out of "white" paper. White is a qualitative property.
Quantitative is to observe and measure a value - like the time of flight of a paper airplane.