Measurements of Local Instantaneous Convective Heat Transfer in a Pipe - Single and Two-phase Flow
April 30th, 2018
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This manuscript describes methods aimed at measuring the local instantaneous convective heat transfer coefficients in a single or two-phase pipe flow. A simple optical method to determine the length and the propagation velocity of an elongated (Taylor) air bubble moving at a constant velocity is also presented.
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.
Frequently Asked Questions
What is the main advantage of the thermography technique?
The main advantage is that it is non-invasive and can measure fast variations in wall temperature.
Who demonstrated the procedure?
The procedure was demonstrated by Avram Balas and Yakov Levi, technicians from the laboratory.
What type of flow does the study focus on?
The study focuses on both single and two-phase pipe flow.
How long should the segment of pipe be for the experiment?
The segment of pipe should be 70 centimeters long or more.
What does the technique measure?
The technique measures local instantaneous convective heat transfer coefficients.
What is the significance of measuring heat transfer coefficients?
Measuring heat transfer coefficients is crucial for understanding and optimizing fluid dynamics in various engineering applications.
Executive Industry Relevance
This thermography technique enables precise measurement of local instantaneous convective heat transfer coefficients in single and two-phase pipe flows, supporting mechanistic de-risking in thermal management systems. By capturing rapid temperature variations non-invasively, it provides quantitative data for predictive modeling of heat transfer dynamics in fluid systems relevant to bioprocessing equipment design and scale-up. The method supports target validation of thermal performance parameters in preclinical device testing and process optimization workflows.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of thermal transport mechanisms in fluidic systems, supporting hypothesis testing of heat transfer behavior under controlled flow conditions.
- Operational Value: Provides reproducible, quantitative local heat transfer coefficient data for validating thermal models in bioreactor design and microfluidic platform development.
Screening & Assay Development
- Scientific Value: Generates standardized, ensemble-averaged heat transfer metrics under defined flow regimes, enabling comparative analysis of thermal performance across fluid formulations.
- Operational Value: Supports assay readiness by delivering reliable, repeatable thermal response data under single and two-phase flow conditions for sensor calibration and system validation.
Translational & Preclinical Research
- Scientific Value: Facilitates mechanistic de-risking of thermal management strategies in implantable devices and drug delivery systems by characterizing convective heat transfer under physiologically relevant flow scenarios.
- Operational Value: Enables continuity from bench-scale thermal characterization to preclinical validation through transferable measurement protocols and normalized data outputs.
Pipeline & Workflow Integration
The method integrates into discovery workflows by providing quantitative thermal readouts that inform early-stage design decisions for fluid-handling systems, with direct relevance to lead identification phases where thermal stability and heat dissipation are critical quality attributes.
- Discovery Biology: Supports hypothesis testing of thermal behavior in fluidic microenvironments, aiding in the de-risking of targets dependent on thermal regulation.
- Screening: Delivers reproducible, quantitative heat transfer coefficient measurements under controlled flow, enabling standardized comparison of thermal performance across experimental conditions.
- Analytics: Produces localized, time-resolved temperature data and ensemble-averaged convective coefficients that facilitate statistical analysis of thermal transients in fluid systems.
- Translational Research: Connects bench-scale thermal measurements to preclinical device validation through consistent methodology and scalable test section design.
- Enterprise Reuse: Establishes a reusable thermal characterization platform applicable across multiple fluid systems and flow configurations, reducing redundant method development.
Operational & Enterprise Impact
- Scientific Value: Enhances predictive confidence in thermal modeling by delivering high-resolution, non-invasive measurements of instantaneous convective heat transfer.
- Operational Value: Ensures standardization and reproducibility through well-defined test section fabrication and synchronized data acquisition protocols.
- Strategic Value: Reduces late-stage biological risk by enabling early identification of thermal management limitations in device and process designs.
- Portfolio Impact: Informs risk-adjusted advancement decisions by providing quantitative thermal performance data for go/no-go evaluations in thermal-sensitive applications.
Implementation Considerations
- Requires expertise in thermography, fluid dynamics, and microfabrication for test section assembly and optical probe integration.
- Dependent on infrared camera systems, data acquisition hardware, and optical probes for bubble tracking and temperature monitoring.
- Necessitates cross-team standardization of flow conditions, bubble injection protocols, and reference state establishment for comparable results.
- Involves adaptation considerations when extending to different pipe diameters, fluid properties, or flow orientations beyond vertical configurations.
- Practical limitations include the need for optically accessible test sections and careful synchronization of thermal measurements with bubble passage events.
Biopharma FAQs
Why does measuring local instantaneous heat transfer coefficient matter for target validation?
Measuring local instantaneous heat transfer coefficient provides quantitative insight into thermal transport mechanisms under controlled flow, enabling hypothesis testing of thermal behavior in fluidic systems relevant to target validation in preclinical device development.
How does isolating the independent variable of bubble position support discovery pipeline objectives?
Isolating bubble position as an independent variable enables precise correlation of thermal transients with specific flow events, supporting mechanistic de-risking and reproducible data generation in early discovery workflows.
What do quantitative dependent variable measurements of wall temperature enable in assay development?
Quantitative wall temperature measurements enable calculation of local convective heat transfer coefficients, providing standardized, reproducible thermal readouts essential for assay readiness and sensor calibration in fluid-based systems.
Why do replication requirements matter for cross-functional collaboration in thermal characterization?
Replication under identical conditions allows ensemble averaging to produce reliable, statistically significant heat transfer data, ensuring consistency across teams and supporting collaborative validation of thermal models.
What statistical analysis capabilities are required before implementing this thermography technique in R&D workflows?
Implementation requires capability to synchronize thermal measurements with bubble passage, perform ensemble averaging of multiple runs, and analyze normalized heat transfer coefficients relative to single-phase flow baselines for meaningful comparative analysis.
