Prediction and Attainment Capability for Quasi-Steady Internal Condensing Flows: An Integrated Experimental/Computational Approach

Michigan Technological University, Houghton MI

Investigators

Abstract

Proposal Number: CTS-0086988 Principal Investigator: A. Narain Abstract Achievement of steady or quasi-steady annular or stratified internal condensing flows in pipe (for any given inlet pressure, mass flow rate, and condensing surface temperature distribution) is dependent on compatibility between the condenser-section heat removal rate and exit pressure condition, or, equivalently, exit vapor flow rate fraction. For certain exit conditions, quasi-steady wavy-interface flows are realized and, for other conditions, significant compressibility-induced oscillations will persist. These unresolved issues will be experimentally investigated with the help of electronic flow control techniques which assist in identifying the range of conditions for which quasi-steady flows are achievable for different exit conditions. The experiment will also allow for novel observations and measurements for annular film condensation in 6.35 mm inner diameter pipe of 0.8 m length. The pipe, and subsequently channel, may operate from vertically downward to horizontal configurations. We also propose to measure time-varying condensate film thickness by fluorescence technique applicable to boiling and condensing flows of doped di-electric refrigerants such as FC-72, etc. From these measurements, mean and wave-structure may be found. Separate efforts relate the results of the proposed experimental research to computational simulations and applications such as Looped Heat Pipes, etc.