Water ( ρ= 1000 kg/m3; Cp= 4.2 kJ/kg.K; k= 0.58 W/m.K ) at 1,537 kg/hr and 26oC enters a 10-mm-diameter smooth tube whose wall temperature is maintained at 79oC. If the water's Nusselt number (Nu) = 375, and the tube length is 7.6, calculate the water outlet temperature,in oC.

In: Mechanical Engineering

V5 What is the water elevation in reservoir B given the following:

Elevation of reservoir A =2250m. The flow is 25m^3/sec. the temperature is 20C

there are two pipes in series with the following characteristics

D1 L1 D2 L2

2 m 1500m 1.6m 1000m

There are gate valves at the exiting and entering the reservoirs

There are two bends, 1 in each pipe size.There is is a globe valve on the downstream pipe.

What is the elevation of Reservoir B?

In: Mechanical Engineering

choose the best answer:

A-
An ideal gas enters an adiabatic nozzle at 10 m/s and exits at 300
m/s. If the incoming specific enthalpy of the gas is 2,111 kJ/kg,
what is the exiting specific enthalpy of the gas in
kJ/kg?

Choices: 1: 2021.1 Kj/Kg , 2: 2200.9 kj/Kg , 3: 92011 Kj/Kg ,
-2021.2 kj/Kg.

B- A material with a specific heat, Cp, of 5 kJ/kg-K passes
through an insulated turbine at 4 kg/s. The incoming temperature of
the material is 100°C and the exiting temperature is 50°C.
Determine the shaft work in kW.

Choices: 1: 1000 KW , 2: -1000 KW , 3: 250 KW , 4: -250
KW.

C- Which of the following statements about a well-insulated
heat exchanger is false (ignoring kinetic and potential energy
changes):

Choices: 1: heat is exchanged between the system and the
surroundings , 2: the 2 materials do not physically mix , 3: energy
is exchanged between the materials , 4: the sum of the enthalpy
changes equals zero.

D- An open vat contains 1 kg of boiling ammonia at 1 bar.
Calculate the time (in seconds) it takes for the vat to empty if
the heat is added at a rate of 100 kW?

Answer: ?

In: Mechanical Engineering

**Crude oil is rarely produced alone as it is generally
commingled with water that creates a number of problems during oil
production. Emulsion is a dispersion of droplets of one immisicible
liquid into another. Evaluate the factors influencing the stability
of emulsions**

In: Mechanical Engineering

Could anyone tell me the best you tube channel or free Unacademy tutor(India) for best learning of Shear force and bending moment diagram along with deflection?

If I satisfied with answer, I would give upvote.

or else I would downvote

Thank you in advance.

In: Mechanical Engineering

A generous amount of gel is applied to the surface of the window of an ultrasound probe prior to its use. The window is made of a polycarbonate material of density ρ = 1200 kg/m3, thermal conductivity k = 0.2 W/m · K, and specific heat cp = 1200 J/kg · K. The probe is initially at a temperature of Ti = 20°C. To ensure that the gel remains adhered to the probe until the probe is brought into contact with the patient's skin, its temperature-dependent viscosity must not fall below a critical value. This corresponds to a requirement that the maximum gel temperature remain below 12°C prior to making contact with the patient. Determine the required initial gel temperature. The thermal conductivity, density, and specific heat of the gel may be assumed to be those of liquid water.

The correct method is to use the Surface Convection of Transient Conduction (Case 3 in Theodore Bergman, Adrienne Lavine 8th edition - Page 289, Equation 5.66)

In: Mechanical Engineering

Design a parallelepiped-shaped float to be constructed of a
polymer with relative density Sg = 0.4, so that it is able to
support you and your co-worker on top and stay out of the water
3cm. Justify each design decision qualitatively and quantitatively
and present the figure.

weight of me and my conworker is 165kgIn: Mechanical Engineering

project question:

'Design and build a thrust measurement system for model aircraft engines '

1- Questions

i) sketch

ii) ideas

iii) plan

iv) introduction, background, theory , abstract etc...

In: Mechanical Engineering

**2 kilogram of R-134a fills a 0.14-m3 weighted
piston–cylinder device at a temperature of –26.4°C. The container
is now heated until the temperature is 100°C. Determine the final
volume of the R-134a.**

In: Mechanical Engineering

Hot water from a boiler of power plant are discharged through a 0.2-m-diameter, thin-walled pipe with a velocity of 3.5 m/s. The pipe passes through a room whose air temperature is 3°C and the exterior surface of the pipe is uninsulated and pipe length is 30 m.

(a) At a position in the pipe where the mean water temperature is 40°C, determine the heat loss and the pipe wall temperature.

(b) If the pipe is covered with a 20-mm-thick layer of insulation (k = 0.5 W/m K) what are the pipe wall temperature, the outer surface temperature, and the heat loss?

In: Mechanical Engineering

Explain the difference between the principle of impulse & momentum approach and the conservation of impulse & momentum approach.

In: Mechanical Engineering

**Develop** and explain each step the
**general equation of heat transfer by conduction** in
a constructive way starting from an element general differential in
the cartesian coordinate system and then reduce to get:

1) Laplace's equation (in R3)

Δ? = 0

2) The Poisson equation (with constant thermal conductivity
?)

Δ? + ? '''= 0

Δ is the Laplacian operator and ? ''' is a source term.

Note: start the analysis from a differential element with volume
??????. Make a energy balance over this volume considering that it
can increase if temperature in time according to its thermal
capacity. Give more generality to the model assuming there is a
source term ? ''' which can be a source that produces thermal
energy or consume it.

In: Mechanical Engineering

Fully developed (both hydrodynamic and thermal) laminar flow is pushed through a thin-walled circular pipe of diameter 13 mm. The fluid flows through the pipe at a velocity of 0.1 m/sec, has a density of 1000 kg/m^3, a dynamic viscosity of 855 x 10^-6 Pa-sec, a specific heat of 4000 J/kg-K, a Prandtl number of 8, and a thermal conductivity of 0.613 W/(m-K).

The outside of the pipe is subjected to uniform cross flow where the free-stream velocity is 5 m/sec, the density is 1 kg/m^3, the dynamic viscosity is 180 x 10^-7 Pa-sec, the Prandtl number is 0.7, the specific heat is 1000 J/(kg-K), and the thermal conductivity is 0.02 W/(m-K).

The pipe (remember the flow is fully developed everywhere) is 10 m long and is wrapped with a thin heater that is generating uniform flux around the periphery of the pipe.

A) What is the specific thermal resistance (K-m^2/W) at a point 5 m into the pipe from the interior surface of the wall to the mean fluid temperature?

B) Using the conditions outlined above for the isoflux pipe in cross-flow, what is the specific thermal resistance (K-m^2/W) from the outside surface of the pipe (or thin heater surface if you want to think of it like that) to the free stream cross-flow fluid?

In: Mechanical Engineering

The
volume of states 1, 2 and 3 of a diesel cycle are 157, 13 and 23
fr^3 respectively. Determine the hp of the engine if the heat input
is 550 BTU/min

In: Mechanical Engineering

As a lubricant engineer, you design a new friction modifier as an additive for synthetic oil to reduce friction between two surfaces. Describe the content of your new friction modifier and mechanism to protect the surface.

In: Mechanical Engineering