Ceramic tubes membrane technology as a new humidification technique for gas turbine inlet air cooling

• Ceramic tubes enhanced the heat and mass transfer between the air and vapor.
• A maximum air temperature drop of 10 °C is obtained.
• Data compared very good with the heat transfer for staggered tube bank.
• The evaporation process does not follow the isenthalpic lines.
• The relative humidity increased from 2% to 5.4%.

An experimental study is conducted to cool ambient air using a new humidification technique. A wind tunnel is built with a test section comprising a matrix of ceramic tubes. These ceramic tubes are of porous design to achieve air cooling by humidification. Ambient air passes over the ceramic tubes matrix (cross flow) whereas water passes through the ceramic tubes. Air temperature and relative humidity data are measured upstream and downstream of the ceramic tube bundle used to humidify the ambient air for several air and water flow velocities. Air velocity is measured at different locations along the centerline of the rectangular wind tunnel's cross section before the test section. Results show that the ambient temperature drops by about 10 °C when the relative humidity increases from 2% to 5.4%. Heat and mass transfer analyses are made and show good agreement with correlations available in the literature. It is noticed that the evaporation process does not follow the isenthalpic lines. Therefore, heat is transferred from the air as latent and sensible heats. A 25% decrease in the duct air outlet temperature is obtained as the water velocity increased to 0.0347 m/s (9.81 × 10−7 m3/s). The results also show that the maximum estimated evaporative cooling system efficiency of the test section is about 45%.

An experimental study was conducted to cool the outdoor air using a new humidification technique. A wind tunnel was built with a matrix of ceramic tubes test section. An outdoor air passed over a ceramic tube matrix (cross flow) where water passing through the ceramic tubes. Air temperatures and relative humidity were measured before and after the test section for several air and water velocities. Air velocity is measured before the test section at different locations along the centerline of the rectangular wind tunnel cross section. Results showed that the ambient temperature drops by about 10 °C when the relative humidity increases from 2% to 5.4%. Heat and mass transfer analyses were made and showed good comparison with the available correlations in the literature. Fig. 1 shows the ceramic tubes test section used in the current experiment.Figure optionsDownload as PowerPoint slide