Boiling sound

The following phenomena pertaining to bubble departure from a heated surface are discussed in this section bubble size at departure, departure frequency, boiling sound, and heat transfer effects by departing bubbles. 

Sounds with a boiling point above 100° C). Figure 25-42 presents an lustration of the Method 0010 sampling train. Comprehensive chemical analyses, using a variety of applicable analytical methodologies, are conducted to determine the identity and concentration or the organic materials. 

The literature on sucrose loss in manufacture is extensive, but not all studies have been conducted on the principles of sound scientific method. An example from the literature of a study with questionable results is a report by Cecil,62 on the effect of pH on sucrose loss during boiling in the open-pan sulfitation (OPS) process. The OPS process is used in some tropical sugar cane growing areas to produce small amounts of a sugar product known as gur, panela, or piloncillo for local consumption. Juice (massecuite from Kenyan OPS mill diluted to 20... 

Knowledge of dominant two-phase flow patterns in micro-channels is a key factor in developing accurate and physically sound predictive tools for heat sink design. Unfortunately, interfacial interactions between the vapor and liquid phases during flow boiling in a micro-channel are often far too complex to permit accurate measurement or quantitative assessment of flow patterns. 

The advantage of this approach is that it uses data that is both available and accurate. Such boiling points are obtained during processes of purification, so the given data often refers to a pure substance and this constitutes sound data. 

Figure 2.12 The sound of boiling methanol on a case Vs-in., horizontal, steam-heated copper tube at 1 atm. (From Westwater et al., 1955. Copyright 1955 by American Association for the Advancement of Science, Washington, DC. Reprinted with permission.)...

A physical explosion, for example, a boiler explosion, a pressure vessel failure, or a BLEVE (Boiling Liquid Expanding Vapor Explosion), is not necessarily caused by a chemical reaction. Chemical explosions are characterized as detonations, deflagrations, and thermal explosions. In the case of a detonation or deflagration (e.g., explosive burning), a reaction front is present that proceeds through the material. A detonation proceeds by a shock wave with a velocity exceeding the speed of sound in the unreacted material. A... 

The most useful descriptions of the various types of boiling would be mathematical expressions that fit the physical observations. The available meager theories are described in the sections which follow. This section is concerned with two supplementary methods for describing boiling the visual appearance of boiling and the sound of boiling. 

Not only do the types of boiling look different, they sound different as well. Technical operators in charge of evaporators, reboilers, and other boiling equipment sometimes judge the operation of their equipment from the noise emitted. 

The sound emitted from methanol boiling on a copper tube at 1 atm. has been measured (W2). No forced convection was used. Figure 10 shows how the sound, in total decibels for the frequency range of 25 to 7500 cycles/sec., varies with the temperature difference. Nucleate boiling... 

---