Noting from Figure 13.16 that gas emissivity can be

Chapter , Problem 13.134

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Noting from Figure 13.16 that gas emissivity can be increased by adding water vapor, it is proposed to enhance heat transfer by injecting saturated steam at 100C at the entrance of the pipe of 13.133. The mass flow rate of injected steam is 50% of the mass flow rate of water vapor in the combustion products. Determine the gas radiation to the pipe wall without and with steam injection. Hint: The temperature of the hot gas decreases, and the partial pressures of the water vapor and CO2 change when relatively cool steam is injected. Use your knowledge of gas mixtures from thermodynamics to calculate the partial pressures and mass flow rates. Assume the molecular weight of the original mixture is that of air.