Propagation of Pressure Waves in a Mixture of Water and Stream

Abstract

The velocity of sound in mixtures of water and steam has been computed from the slope of the lines of equal entropy over a wide range of ambient conditions up to the critical point. The sound velocity is lower in the mixture than in either constituent It changes discontinuously on transition to the single phase in wet steam with just a trace of liquid The velocity is about 10 per cent less than in dry steam. The velocity decreases monotonically with increasing water content. In boiling water the velocity is very low. The smallest value occurs at reduced pressure at the triple point (with no solid ice present); the velocity here is as low as 0.012 m/s Rankine-Hugoniot curves were calculated for the mixture. These show that a shock-like compression in very wet steam or boiling water will condense all the steam giving rise to a large change in volume with very little rise in pressure. The Hugoniot curve lies very close to a line of constant entropy in this case. For high quality steam the compression will raise the temperature of the vapor and evaporate the liquid phase. This occurs far from constant entropy conditions, indicating a strong loss mechanism. In boiling water the propagation was studied with pressure waves having an amplitude exceeding the minimum necessary to condense all the steam. The velocity decreases monotonically with decreasing driving pressure, approaching the small amplitude acoustic velocity when the driving pressure approaches the minimum necessary to condense all the steam. In a straight pipe of boiling water true shocks were not propagated. The rise time of the compression wave steadily increases as it passes through the medium. On finally reaching a region of no bubbles, high peak pressures are observed. These peaks were an order of magnitude greater than the original driving pressure. This amplitude is apparently due to the formation of a water hammer.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1961
Accession Number
ADA396445

Entities

People

  • H. B. Karplus

Organizations

  • IIT Research Institute

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acoustic Propagation
  • Acoustic Properties
  • Acoustic Velocity
  • Acoustic Waves
  • Acoustics
  • Fluids
  • Heat Capacity
  • Heat Energy
  • Heat Transfer
  • Latent Heat
  • Measurement
  • Pressure Gages
  • Pressure Measurement
  • Shock Waves
  • Sound Waves
  • Water Hammer
  • Waves

Readers

  • Combustion Dynamics and Shock Wave Physics.
  • Combustion and Flow Dynamics.