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In the fields of cryogenic engineering and energy equipment, LNG (liquefied natural gas) systems place extremely high demands on insulation materials. These materials not only need stable thermal conductivity but also must maintain structural integrity under extremely low temperatures. LNG elastic felt is a widely used cryogenic insulation material for such applications. This article will provide a systematic analysis of the thermal conductivity of LNG elastic felt.
I. Special Requirements for Thermal Conductivity in Cryogenic Insulation
Unlike room temperature insulation, the thermal conductivity of materials faces multiple challenges under cryogenic conditions:
Extreme temperature difference and strong thermal driving force
Conventional materials are prone to embrittlement or performance degradation
Freezing water vapor significantly increases thermal conductivity
Therefore, the thermal conductivity of LNG elastic felt must remain stable within the cryogenic range; this is the core value of its engineering applications.
II. Material Structural Characteristics of LNG Resilient Felt
LNG resilient felt typically consists of the following structure:
Flexible fiber or composite fiber layer
Multi-layered low thermal conductivity structure
Surface protection or composite reinforcement layer
This structural design balances low thermal conductivity, flexibility, and low-temperature adaptability.
III. Formation Mechanism of Thermal Conductivity of LNG Resilient Felt
1. Multi-layered fiber structure extends the heat conduction path
LNG resilient felt is composed of a large number of interlaced fibers:
Heat must repeatedly circulate between fibers
The actual heat transfer path is significantly lengthened
The thermal conductivity efficiency is thus reduced
This structural "superposition of thermal resistance" is a crucial basis for its low thermal conductivity.
2. Static gas layer inhibits heat transfer
The fiber structure encapsulates a large amount of static gas:
Gas convection is effectively suppressed
Heat is mainly conducted through molecules
The overall thermal conductivity is significantly lower than that of dense materials
In low-temperature environments, the static gas layer can still provide stable insulation.
3. Flexible Structure Reduces Thermal Bridge Effect
LNG elastic felt possesses excellent flexibility and resilience:
It can tightly adhere to the surfaces of cryogenic pipelines and equipment
It reduces installation gaps
It lowers the probability of thermal bridge formation
This has a significant impact on the thermal conductivity of the actual system.
IV. Stability Analysis of Thermal Conductivity under Cryogenic Conditions
1. Resistance to Cryogenic Embrittlement
In cryogenic environments, some materials undergo structural embrittlement, leading to uncontrolled thermal conductivity.
LNG elastic felt is designed with emphasis on:
Fiber flexibility
Structural continuity
Thus maintaining predictable thermal conductivity at low temperatures.
2. Impact of Moisture and Frost Prevention on Thermal Conductivity
When moisture enters the insulation layer:
Freezing significantly increases thermal conductivity
It damages the original insulation structure
LNG elastic felt is typically used in conjunction with protective structures to reduce the impact of moisture intrusion on thermal conductivity.
V. Main Factors Affecting the Thermal Conductivity of LNG Elastic Felt
1. Fiber Density and Compression Degree
Excessive compression increases the proportion of solid thermal conductivity.
Insufficient density may reduce structural stability.
Appropriate density is key to achieving stable thermal conductivity.
2. Installation Process and Layer Overlap
Improper joint treatment can easily lead to thermal bridging.
Multi-layer staggered laying helps reduce concentrated heat conduction.
3. Ambient Temperature Gradient
In cryogenic systems with extreme temperature differences:
Radiative heat transfer may increase.
The thermal conductivity needs to be comprehensively evaluated based on system design.
VI. Significance of LNG Elastic Felt's Thermal Conductivity in Engineering
From an engineering perspective, the advantages of LNG elastic felt's thermal conductivity are reflected in:
Reducing cold loss of cryogenic media
Reducing the risk of frosting and condensation
Improving system operational safety and energy efficiency stability
This makes it one of the important choices for insulation of cryogenic pipelines, storage tanks, and equipment.
In summary, the thermal conductivity of LNG elastic felt stems from its multi-layered fiber structure, stable gas insulation layer, and excellent low-temperature adaptability. Under proper design and construction conditions, it can maintain stable insulation performance in low-temperature environments for extended periods, making it one of the most valuable insulation materials for cryogenic engineering.
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