Pressure Drop During Condensation in Microchannels

The paper reports preliminary results from a new research programme for making accurate heat transfer and pressure drop measurements during condensation in microchannels. While commissioning the apparatus a dummy test section was used with identical channel and header geometry to that to be used in the main test program (The final test section will comprise a relatively thick copper test section containing 98 accurately located thermocouples for measuring the temperature distribution from which local heat flux and temperature at the microchannel surface will be obtained). While using the dummy test section (without embedded thermocouples) the opportunity was taken to make accurate pressure drop measurements while measuring the vapor flow rate and total heat transfer rate based on coolant measurements. Data have been obtained for FC72 and steam. Approximate comparisons with available pressure drop calculation methods are presented.