Misure di scambio di calore convettivo istantanea locale in un tubo - flusso singolo e due fasi

Overview

This manuscript presents a thermography technique for measuring local instantaneous convective heat transfer coefficients in single or two-phase pipe flow. The method is non-invasive and can capture rapid variations in wall temperature due to time-dependent flows.

Key Study Components

Area of Science

• Thermography
• Convective heat transfer
• Fluid dynamics

Background

• Understanding transient convective heat transfer is crucial for various applications.
• Single and multi-phase flows present unique challenges in measurement.
• Non-invasive techniques are preferred for accurate data collection.
• Elongated air bubbles can affect flow characteristics and heat transfer.

Purpose of Study

• To develop a method for accurately measuring heat transfer coefficients.
• To address key questions in transient convective heat transfer.
• To demonstrate a technique that measures fast variations in wall temperature.

Methods Used

• Utilization of a well-designed test section for measurements.
• Implementation of a thermography technique.
• Measurement of elongated (Taylor) air bubbles in pipe flow.
• Non-invasive observation of temperature variations.

Main Results

• The technique successfully measures local heat transfer coefficients.
• Fast variations in wall temperature were accurately captured.
• Results contribute to understanding transient behaviors in fluid flows.
• The method is applicable to both single and two-phase flows.

Conclusions

• The thermography technique is effective for heat transfer measurement.
• Non-invasive methods provide valuable insights into flow dynamics.
• This study enhances the understanding of convective heat transfer in various applications.

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