Condensation mass flow rate

On the other hand, because of dQ = Ahv dM, with the condensate mass flow rate dM given by (4.10), the last equation is transformed into... 

The condensate mass flow rate per unit width T(x) is given by... 

The correlation of Akers, et. al., has given good results in some industrial designs. The authors report that some vertical and inclined tube data is also correlated on the same basis. The sharp break in the data occurs around a Reynolds number of 5 X lO as shown in Figure 10-75. The mass flow rate used to correlate is the arithmetic average of inlet and oudet liquid condensate and vapor flows ... 

The total heat flow (Q) at the film surface is equal to the mass flow rate (W k) times the heat of condensation (AH). That is, the heat generated by condensation at the surface must be equal to the heat transported away by conduction and radiation for steady state to be achieved. In mathematical terms this results in the equation. 

From the design viewpoint, Eq. (78) could be coupled with Eq. (71) to obtain an approximation of the system performance and if the liquid temperature profile can be estimated, the same procedure can be followed with Eq. (80). However, in general the design engineer needs to use analytical expressions for the absolute rates of vaporization and condensation, so that with a knowledge of the rate terms and the other parameters, Eqs. (71) and (72) could be solved for the temperature and mass flow-rate profiles. 

The flow of gas-liquid mixtures in pipes and other items of process equipment is common and extremely important. In some cases the quality, that is the mass fraction of gas in the two-phase flow, will vary very little over a large distance. An example of this is the flow in many gas-oil pipelines. In other cases, boiling or condensation occurs and the quality may change very significantly although the total mass flow rate remains constant. 

Gieseler et al. utilized tunable diode laser absorption spectroscopy to detect water vapor concentrations, gas velocities and mass flow during freeze-drying of pure water at different pressure and shelf temperature settings and of a 5%w/w mannitol solution. The analyzer was interfaced to the spool that connected the dryer chamber to the condenser. The reported method was advantageous in that primary and secondary drying end-point control based upon mass flow rate was independent of freeze-dryer size and configuration. ... 

A simple Rankine cycle using water as the working fluid operates between a boiler pressure of 500 psia and a condenser pressure of 20 psia. The mass flow rate of the water is 31bm/sec. Determine (1) the quality of the steam at the exit of the turbine, (2) the net power of the cycle, and (3) the cycle efficiency. Then change the boiler pressure to 600 psia, and determine (4) the quality of the steam at the exit of the turbine and (5) the net power of the cycle. 

In a Rankine power plant, the steam temperature and pressure at the turbine inlet are 1000°F and 2000 psia. The temperature of the condensing steam in the condenser is maintained at 60° F. The power generated by the turbine is 30,000 hp. Assuming all processes to be ideal, determine (1) the pump power required (hp), (2) the mass flow rate, (3) the heat transfer added in the boiler (Btu/hr), (4) the heat transfer removed from the condenser (Btu/hr), and (5) the cycle thermal efficiency (%). 

Water is the working fluid in an ideal Rankine cycle. The condenser pressure is 8kPa and saturated vapor enters the turbine at (1) 15 MPa, (2) 10 MPa, (3) 7 MPa, and (4) 4 MPa. The net power output of the cycle is 100 MW. Determine for each case the mass flow rate of... 

Determine the effieieney and power output of a reheat Rankine eyele, using steam as the working fluid, in whieh the eondenser pressure is 80 kPa. The boiler pressure is 3 MPa. The steam leaves the boiler at 400°C. The mass flow rate of steam is 1 kg/see. The pump efficiency is 85% and the turbine efficiency is 88%. After expansion in the high-pressure turbine to 800 kPa, the steam is reheated to 400°C and then expanded in the low-pressure turbine to the condenser. 

At a geothermal energy source, dry steam at 700 kPa and 170°C is available at a mass flow rate of lOOkg/sec. A barometric condenser at lOkPa is used to decrease the turbine exhaust temperature. Find (a) the power produced by the geothermal power plant as shown in Fig. 2.22a. (b) What is the power produced without the barometric condenser ... 

At a geothermal energy source, a mixture of 80% steam and 20% water at 140°C is available at a mass flow rate of Ikg/sec. A barometric condenser... 

Condenser temperature Boiler temperature Mass flow rate of ammonia... 

Determine the pump power, turbine power, net power output, rate of heat added to the heat exchanger by surface ocean warm water, rate of heat removed from the heat exchanger by deep ocean cooling water, cycle efficiency, boiler pressure, condenser pressure, mass flow rate of surface ocean warm water, and mass flow rate of deep ocean cooling water. 

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