Q1. You want to keep the indoor temperature of an office at 25oC. The outdoor temperature is 5oC. The heat transfer through the building’s exterior is 3 x 106 kJ. To achieve the desired indoor temperature, you are exploring three heat pumps operating between the office interior and: (i) the ground at 12oC; (ii) a pond at 10oC; and (iii) the air outside at 5oC.

For each case, what is the minimum theoretical net work input (in kJ) any heat pump would require?

What are some topics to discuss relating to the public, safety, and welfare in regards to the challenger space shuttle explosion?

Consider a steam power plant operating on a simple ideal Rankine cycle in which the steam enters the turbine at 3 MPa and 350C and is condensed in the condenser at 75 kPa. Determine the thermal efficiency of this cycle and sketch an appropriately labeled T-s diagram. Also compare this thermal efficiency to that a Carnot heat engine operating between these same two limits.

The change in enthalpy across the pump = work done by the pump: h2-h1= v1(P2– P1)

5. Estimate the life (in hours) of an 02-series single-row deep-groove ball bearing with a 50-mm bore working under the following condition: axial force = 4 kN, radial force = 6 kN, outer ring rotating at 360 rpm, temperature = 50 °C, light impact, reliability = 97%. (6 points)

Air enters a turbine operating at steady state at 6 bar, 1200 K and expands to 0.8 bar. The turbine is well insulated, and kinetic and potential energy effects can be neglected.

Assuming ideal gas behavior for the air, what is the maximum theoretical work that could be developed by the turbine in kJ per kg of air flow?

Discuss potential methods to linearize body source terms in search for a stable solution and

Describe:

-Relations that could be used to couple pressure and density with heat addition

-The role or meaning of characteristic curves in a flow field

-Shock-capturing techniques in flow fields

Discuss potential methods to linearize body source terms in search for a stable solution and

Describe:

-Relations that could be used to couple pressure and density with heat addition

-The role or meaning of characteristic curves in a flow field

-Shock-capturing techniques in flow fields

Describe:

Where the pressure and density relations are used in SIMPLE-based solutions.

The need for characterizing or defining the compressibility constant.

The most important computational rules in an iterative solution process.

Discuss the:

-Motivation for introducing the upwind schemes of Godunov as a method of solution.

-Requirements for different pressure correction equations in an iterative solution process.

-Means for having velocity-to-pressure coupling, and then pressure-to-density coupling.

Re-derive an expression for average NuL (= hLL/k) for flow over a flat plate by integrating the expression for average hL for a mixed BL. For Rex,cr, use 123456 (keeping the same sequence), and find the constant B (in Eq. 7.38). Also show that for Rex,cr = 500,000, B is indeed equal to 871.

eq. 7.38=> NuL=(0.037 ReL^(4/5)-B)Pr^(1/3)

0.6<=Pr<=60

Rex,c <= ReL <=108

In a low temperature drying system, air at 60°C and 10% Relative humidity passes over a bed of diced carrots at 20 kg-dry air/sec. The rate of water removal from the carrots Is measured by difference in total weight over time and found to be approximately .16 kg-water/sec. In the system described above, calculate the temperature and relative humidity of the air exiting the drying system.

A fuel with a stoichiometric formula of C99H148O56N is being combusted at a rate of 1 metric tonne/hr in 100% excess air.

[1] Calculate the rate of air supply to the combustion chamber.

[2] Calculate the rate of CO2 production from the combustion chamber.

Please prove that in homogeneous nucleation of solidification the critical radius and activation energy are ??? = (? 2??????) ( 1 ) and ???? = (16????3????2 ) 1 , respectively, ????? ??? 3?????2 ???2 in which ? is the surface free energy, Tm is the melting temperature, ?T is the degree of supercooling (Tm - T), and ?Hf is the latent heat of fusion.

1a. The relative humdity outdoor is 70% and the outdoor temperature is 90 degree F what is the actual partial pressure of water vapor in the air

1b. Humidty ratio (w) is the ratio of the mass of the water (Mw) to the mass of dry air (Mw) note that two partial pressures sum to the total pressure (P =Pa + Pv) derive the equation

w = 0.622Pv / (P-Pv). Use the ideal gas equation for mass

1c. Solve for humidity ratio if the partial pressure of water vapor is 0.1816psia

1d. What is the relative humidity of 70 degree F moist air in a classroom

1e. Estimate the mass (Ibm) of water vapor in the classroom