H R, H P and CV are all related to the standard temperature of 25°C. The enthalpy of the entering air is considered to be sensible heat only (i.e. the fuel/air is considered to be a dry mixture).
The enthalpy of the flue gas must be consistent with the calorific value of the fuel which is used in the balance. If the gross calorific value is used, then H R should contain a latent heat term equal to the mass of water produced per kilogram of fuel multiplied by the latent heat of evaporation of water at 25°C (h fg). If the net calorific value is used, then the flue gas enthalpy will consist of sensible heat terms only. In this chapter we are concerned with predicting the temperature reached within the flame, hence the net calorific value/sensible heat terms system is the more appropriate.
KeywordsCombustion Methane Dioxide Welding Enthalpy
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