Consider a flat plate with parallel airflow (top and bottom) characterized by u∞ 5 m/s, T∞ 20°C. Determine the average convection heat transfer coefficient, convective heat transfer rate, and drag force associated with an 2.8-m-long, 2.8-m wide flat plate with a surface temperature of 50°C. Assume the critical Reynolds number is 5x10⁵.

Determine the average convection heat transfer coefficient, in W/m²·K.

Determine the convective heat transfer rate, in W.

Determine the drag force, in N.

Describe the engineering designs associated with vapor space above the tube bundle in a kettle reboiler and liquid levels above and below the tubes.

2. Explain why Charpy impact specimens of steels fractured in the middle of the ductile to brittle transition region fail by brittle fracture in the center and ductile fracture at the edges (See Ref. [10], p. 89).

1. Explain the Betz’s theorem and various terms in the equation

Air enters the compressor of an ideal gas refrigeration cycle at 17°C and 35 kPa and the turbine at 47°C and 160 kPa. The mass flow rate of air through the cycle is 0.3 kg/s. Assume variable specific heats for air.

Determine the net power input.

The net power input is kW.

1) You are responsible for selecting automobiles that will be used in your company’s fleet and have been asked to determine the energy consumption of the described vehicles for each of the driving processes described below. The vehicles have the following combined wind drag and rolling friction force during average operation conditions. The relationship for this force is Ff = (0.214m + 5.63) where, m=vehicle mass and Ff is the combined wind and rolling friction forces in N. Note the numerical parameter have units associated with them.

One automobile is an all-wheel drive hybrid vehicle with a mass of 1450 Kg and it is powered by a storage battery- motor combination that provides electricity to four wheel mounted motors/generators. It does not have plug in capabilities at this time. The batteries in the hybrid configuration are charged using an internal combustion engine-electrical generator combination at the end of the driving cycle or by regenerative braking. The battery in this problem has sufficient energy storage to accomplish the given driving cycle and it is used to keep account of the energy used in each driving process. For the purpose of this problem the battery is initially fully charged. Determine the change in the chemical energy of the battery for each described process for the hybrid vehicle. The efficiency of the battery charging process is 90% when it is charged from the engine. The efficiency of the regenerative braking mechanism is 85% and is defined as the energy provided to the battery divided by the braking energy needed to reduce the speed of the automobile. The battery charging process is included in the regenerative braking efficiency. The battery discharge efficiency is 90%. The battery efficiencies are defined as the energy provided by the battery divided by the change in the chemical energy of the battery during the discharge and the reciprocal of this parameter for the charging phase. The hybrid regeneration braking system can operate down to a velocity of 10 Km/hr when the standard friction brakes are applied. All processes can be considered to be isothermal. The efficiency of the engine-generator system is 34% for the hybrid vehicle. The second automobile has a mass of 1200 Kg, has the same all wheel motor drive configuration and is powered by a conventional internal combustion engine with a generator that has an efficiency of 31%. This efficiency is for the engine-generator combination. In this configuration there is no regenerative braking mechanism and no battery.The different driving cycles are composed of the following individual processes.

a) The vehicle accelerates from a stop to a speed of 50 km/hr at constant elevation. This acceleration takes place over a distance of 75 m. This applies to both the hybrid and nonhybrid vehicle.

b) The vehicle stops from a velocity of 50 km/hr at a constant deceleration rate. During regenerative braking the distanced traveled is 67 m and during frictional braking the distanced traveled is 15 m. This process is also at constant elevation. For the nonhybrid vehicle the braking distance is 78 m.

c) A hill climb with an elevation change of 150 m at an angle of 12 degrees and a constant velocity of 50 km/hr. The drag work should be included in this calculation.

d) Calculate the power from the power device, either the battery or the internal combustion engine vehicle, required during the hill climb described in part (c).

e) A hill descent with an elevation change of 150 m at an angle of 1 degrees and a constant velocity of 50 km/hr. The drag work should be included in this calculation.

f) Energy consumed per km during a level driving distance.

2.1) Determine the chemical energy change in the battery (in the hybrid vehicle) or fuel consumed (nonhybrid vehicle) and the thermal energy (heat) added to the environment (heat flow) for a), b), c), e) and f) of the above driving processes.

2.2) Using the above results and the given information, consider two driving cycles that your company uses. The first is composed of 51 start and stops, 5 hill climbs and descents and a level, constant velocity component of 21 km. The second driving cycle is composed of one start stop, one hill climb and descent and 310 km of level, constant velocity driving. The first driving cycle is used twice as often as the second.

2.3) Based on your calculations, write a recommendation for purchasing the type of vehicles. The company plans to purchase four vehicles. The heating value of gasoline is 32.0 MJ/L. The cost of gasoline is $1.75/liter. The recommendation is to the Chief Financial Officer of the company who has an MBA and a public relations background. To do this problem it will help if you draw your system and identifying the energy property changes and the energy interactions at the boundaries. In some cases, you may need a sub system analysis to identify the energy interaction, especially the heat flows associated with the inefficiencies of the system. Also, there is no external energy input until the end of the driving cycle for the hybrid vehicle, all the driving processes are supplied by the battery. For the nonhybrid vehicle, there is an external energy input from the fuel supplied to the engine for driving process. It will also help if you view this problem as a simulation analysis of fuel consumed by each type of vehicle over each driving cycle. The problem has been sub divided into individual processes that make up the driving cycle.

5a. What is a worm gear reducer?

5b. Why is a worm gear extremely quiet and able to tolerate substantial loads?

1a. What are the different types of speed reducers?

1b. What are the factors considered when selecting the reducer?

Back injuries are very common in humans and are often caused by lifting objects with the legs straight while leaning over; also known as “lifting with the back.” Use the concepts learned in this lab to explain why one should “lift with the legs” rather than with the back. Make sure to discuss the forces and torques involved, and how they differ in the two lifting techniques.

The high and low temperatures of each day in Wichita KS are given in Table. (1 pt) (a) Plot the high temperature for 7 days as a function of day, i.e., high temperature on y-axis, and day # on x-axis. Use the red, empty square as a marker with the solid line. (b) Plot both the high and low temperature for 7 days as a function of day in the same plot. Use the red, empty square as a marker with the solid line for high temperature, and blue, empty circle as a marker with the dotted line for low temperature.

For Octave/Matlab

Mr smith plans to deposit money in a bank that pays 10% interest per year, compounded daily. what the effective rate of interest will he receive (a) yearly, (b) semiannually? Answers (a) 10.515% (b) 5.0625%

Provide five examples of how the Internet of Things (IoT) will influence your career practicing mechanical engineering

o Explain (in detail and with examples) how life and society will benefit from this evolution