To investigate the vapor pressure drop due to the resistance force of tube bundle and the effect on heart transfer
triangular arrangement tube bundle widely applied to falling film evaporator is chosen as the physical model to evaluate the vapor temperature loss
and the fitting coefficient of pressure drop from the experimental data is provided. The effects of steam mass flux
saturated temperature
tube column number and water flow rate on vapor temperature loss are analyzed respectively. The results indicate that the temperature loss increases with the increase of water flow rate
steam mass flux and tube column number
while decreases with the increasing saturated temperature. With the equal steam mass flux
the temperature loss at 45 ℃ is six times of that at 70 ℃ and the temperature loss as water flow rate in 0.08 kg/(m·s)is almost double of that as water flow rate in 0.02 kg/(m·s); the temperature loss rises parabolically with the increasing tube column number in large falling film evaporator. A new design idea of equal temperature loss in each effect evaporator is proposed which facilitates ensuring the heat transfer efficiency.
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references
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