Apparatus for enhancing condensation and boiling of a fluid

Abstract

An apparatus enhances the condensation and boiling of a fluid in heat exchange machines, by directly applying time-periodic acoustic waves with a resonance oscillation frequency to liquid drops and / or bubbles formed on a solid surface, when the fluid is in the process of condensation or boiling, thereby effectively removing them therefrom. The apparatus comprises a signal generator for generating a driving signal based on a resonant oscillation frequency of at least one of the liquid drops and the bubbles; and a vibrator, in response to the driving signal, for providing an acoustic pressure wave to said at least one of the liquid drops and the bubbles, to thereby detach them from the solid surface.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to a condensation and boiling system; and, more particularly, to an apparatus for enhancing condensation and boiling of a fluid in heat exchange machines, by employing the frequency characteristics of liquid drops and / or bubbles formed on a solid surface.[0003] 2. Description of the Related Art[0004] There are various techniques for promoting condensation and boiling of a fluid, performed in heat exchange machines such as refrigerators, air-conditioners, and heaters. The techniques include: mechanically modifying a solid surface of, e.g., a tube or wall of the heat exchange machines, which is in contact with the flowing fluid in the process of condensation or boiling; directly vibrating a solid surface, such as a metal or mirror, with a resonant oscillation frequency of the solid part not of the fluid, as disclosed in U.S. Pat. No. 5,025,187; applying an electric field to a fluid; and coating the solid surface with...

AI Technical Summary

Benefits of technology

[0015] The vibrator 106 may be implemented by using an acoustic speaker, which is capable of easily generating the time-periodic acoustic pressure waves. Alternatively, there may be employed a piston, cam, membrane, or flap associated with a motor, or a piezoelectric device, for the same purpose.

Problems solved by technology

This technique, however, is not gaining popularity since its processing cost is considerably high.

In addition, the pressure drop of the flow is increased because the grooves provided on the solid surface promotes the fouling and scaling in the condensation and boiling system during operation.

The electric-field-applying technique has a problem of its own that a significantly high voltage of several tens of kilovolts (kV) is required for the generation of the electric field, thereby deteriorating the safety thereof.

In the surfactant-coating technique, the performance of condensation and boiling of the fluid becomes lower as the coated surfactant is gradually dissolved, after a certain time, causing serious environmental pollution due to the dissolved surfactant.

The solid-vibration technique is difficult to apply for a shell-and-tube type heat exchange machine and also requires vibration of several tens of kilohertz to be imposed on the system, which consumes a significant amount of energy.

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