Design issues for cryogenic vessels (for storing liquid oxygen, liquid nitrogen)
Thread Content
During the design of the final project, the inner cylinder had a thin wall thickness and a large height; as a result, it failed to meet the stability requirements during vacuum testing for leak detection (under an external pressure of 0.1 MPa). After increasing the wall thickness, in order to reduce the weight of the cylinder, I wonder whether it would be possible to use reinforcing rings. Additionally, it is necessary to consider the tightness of the insulation material made of pearlescent sand in the vacuum layer; therefore, rectangular reinforcing rings were chosen as they do not interfere with the filling of the pearlescent sand. I would appreciate any guidance from the teachers
I’m not quite sure what you mean – are you saying that the wall thickness of the inner cylinder is thin, and that it’s necessary to add reinforcing rings to the inner cylinder?
The reinforcement ring inside the cylinder shouldn’t affect the installation of the insulation layer, right?
1. “The inner cylinder wall thickness is relatively thin, and the cylinder height is large.” Please provide the specific figures. 2. Does “instability occurs when the stability requirement is not met during leak detection (external pressure of 0.1 MPa)” refer to the calculation failing when an external pressure check is performed at 0.1 MPa? 3. “After increasing the thickness to a certain level, in order to reduce the weight of the cylinder, it is possible to install reinforcing rings; moreover, it is necessary to consider the tightness of the packing of the insulating pearlescent sand in the vacuum layer, and rectangular reinforcing rings should be chosen so as not to affect the packing of the pearlescent sand.” In cases where the external pressure resistance of the shell does not meet the requirements, reinforcing rings can be installed. As for the concern regarding the tight packing of the pearlescent sand in the vacuum layer, there is actually no need to worry about it. Generally, inverted angle steel or flat steel is chosen for the reinforcement ring, depending on the effective moment of inertia and the required moment of inertia. Secondly, in terms of the manufacturing process, the filling of the interlayer with pearlescent sand is generally done in a horizontal filling manner, and the interlayer is usually filled while the air inside it is removed. Gas can also be used to push the pearlescent sand into the interlayer (but it is necessary to verify the external pressure on the inner cylinder). If considering raising a vertical device after horizontal filling, it is necessary to provide flow openings for the pearlescent sand in the reinforcement ring located in the direction of the pearlescent sand filling port; this factor is generally not taken into account for horizontal storage tanks.
The thesis supervisor has responded; the inner cylinder reinforcement ring is located inside the cylinder
Leak testing should be carried out under atmospheric pressure, taking stability into account
You designed a low-temperature storage tank; I’m not sure how you calculated the instability of the inner cylinder. Generally, no reinforcement rings are used for the inner cylinder, while reinforcement rings are installed on the outer cylinder. What is the capacity in cubic meters of the storage tank you designed? Was strain strengthening performed?
60 cubic meters; when the inner tank is evacuated for leak testing, it is placed in the atmosphere