Internal review on the state of loss of vacuum research on helium cryogenic systems

TL;DR

This paper reviews the current understanding and challenges of vacuum loss in helium cryogenic systems, emphasizing its impact on thermal performance, safety, and the need for improved predictive models.

Contribution

It provides an internal review of recent research efforts to evaluate heat transfer mechanisms and develop models for vacuum loss in helium cryogenic systems.

Findings

Vacuum failure causes rapid heat transfer and fluid loss.

Current models aim to predict vacuum loss behavior.

Vacuum loss poses safety and operational risks.

Abstract

It is commonplace in helium cryogenic systems to utilize vacuum insulation to mitigate convective heat transfer to the low temperature fluids. While the insulating vacuum meaningfully improves cryogenic system thermal performance, failure of the insulating vacuum results in rapid heat transfer to the cryogenic helium often resulting in loss of fluids from venting, potential over-pressure of the system, and risks damage to vessels and equipment. The nature of the loss of vacuum problem is highly transient and difficult to predict uniformly across applications, although several efforts have incurred in recent decades to evaluate the heat transfer mechanism and develop useful models.