Location

Rolla, MO

Session Start Date

6-11-1999

Session End Date

6-17-1999

Keywords and Phrases

Ventilation; Air Cooling; Auxiliary Fans; Computer Program

Abstract

Taking into consideration the possibility of condensation of water vapour contained in air which flows through a diaphragm cooler, a mathematical model of space-time changes in air temperature, humidity, and also in the temperature of the heat exchanger and the cooling water in the cooler in question was created. In the mathematical description of air-cooling using the above-mentioned cooler two zones was identified. The first concerns the dry cooling of air, while within the second, the process of outdropping of water contained in the cooled air. Each of these zones has been described by applying a system of three partial linear differential equations; these derived from the enthalpic balance of cooled air, the heat exchanger, and cold water. Zones were chosen in the course of continuous observations aimed at establishing whether the cooled air had reached dew point. Since this necessitated a knowledge of the temporary local value of its cooled part, dependencies using average values were insufficient. The correctness of mathematical descriptions adopted was evaluated by comparing results of calculations ensuing from numerical solutions of systems of differential equations derived with those of measurements carried out in mining conditions on a chosen diaphragm cooler. The computer programme thus created makes it possible to:

• determine time variables across the entire spectrum of each cooling zone, and thereby the parameters of air leaving the cooler,

• establish the dynamics of changes in thermal power for diaphragm counter-current air coolers,

• choose optimal - as far as thermal power is concerned - auxiliary fans for forcing the air through the coolers, and to

• analyze existing and design new, more efficient coolers.

Department(s)

Mining and Nuclear Engineering

Appears In

U.S. Mine Ventilation Symposium

Meeting Name

8th U.S. Mine Ventilation Symposium

Publisher

University of Missouri--Rolla

Publication Date

6-11-1999

Document Version

Final Version

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Jun 11th, 12:00 AM Jun 17th, 12:00 AM

Mathematical Description of Air Cooling Using a Mining Diaphragm Cooler Taking Into Consideration the Condensation of Water Vapour

Rolla, MO

Taking into consideration the possibility of condensation of water vapour contained in air which flows through a diaphragm cooler, a mathematical model of space-time changes in air temperature, humidity, and also in the temperature of the heat exchanger and the cooling water in the cooler in question was created. In the mathematical description of air-cooling using the above-mentioned cooler two zones was identified. The first concerns the dry cooling of air, while within the second, the process of outdropping of water contained in the cooled air. Each of these zones has been described by applying a system of three partial linear differential equations; these derived from the enthalpic balance of cooled air, the heat exchanger, and cold water. Zones were chosen in the course of continuous observations aimed at establishing whether the cooled air had reached dew point. Since this necessitated a knowledge of the temporary local value of its cooled part, dependencies using average values were insufficient. The correctness of mathematical descriptions adopted was evaluated by comparing results of calculations ensuing from numerical solutions of systems of differential equations derived with those of measurements carried out in mining conditions on a chosen diaphragm cooler. The computer programme thus created makes it possible to:

• determine time variables across the entire spectrum of each cooling zone, and thereby the parameters of air leaving the cooler,

• establish the dynamics of changes in thermal power for diaphragm counter-current air coolers,

• choose optimal - as far as thermal power is concerned - auxiliary fans for forcing the air through the coolers, and to

• analyze existing and design new, more efficient coolers.