BS/EN 16603-31-02-2018 pdf download.Space engineering-Two-phase heat transport equipment.
4.4.2.2 Mechanical qualification
TPI-ITF are classified as Metallic Special Pressurized Equipment (MSPE) and relevant mechanical requirements are specified in ECSS-ST-E-32.02 and are applied in the present Standard for all TPHTE types.
For qualification of a TPI-ITE as pressurized component, the main characteristic is the internal pressure, which varies in relation to the exposure temperature of the unit (temperature dependent saturation pressure of the heat carrier liquid).
F.CSS-ST-E-32-(J2 specifies qualification requirements for heat pipes (see figure
4.12 and Table 4-8 of ECSS-E-ST-32-02). The present Standard selects
qualification requirements for TPHTE, which have seen proof pressure tests
1.5 MDP, Testing is the preferred method rather than qualification by fracture
control analysis.
For qualifying a TI’HTE with respect to external mechanical environment the following mechanical tests are considered:
• Constant or static acceleration
• Sine vibration
• Random vibration
For these tests the qualification unit needs to be rigidly mounted to the test equipment (vibration table). I lowever, such mounting provisions can have only reduced similarity to real applications in spacecraft and the meaningfulness of such tests is, therefore, very often reason for discussion under experts. For heat pipes it is common understanding not to perform these tests en long heat pipe profiles for the following reasons:
• The length of the test heat pipe is adapted to the test equipment and is therefore shorter as in many realistic spacecraft applications.
• The application of heat pipe is often for embedding them in sandwich structures. Mechanical loads for these applications are quite different as can be simulated with a rigidly fixed single heat pipe profile.
• Several capillary structures, in particular axial groove heat pipes, are quite insensitive to mechanical loads and tests as suggested in existing procedures can be unnecessary.
For many TPHTE applications (in particular for devices with simple capillary structures, e.g. axial grooves) the formal mechanical qualification can be therefore performed with the first structural model on satellite level. In case the risk for such a late qualification is high, pre-qualilication can be performed on unit or part level in particular for the following cases:
• The TPHTE,. in particular a heat pipe, has a capillary structure, which is sensitive towards mechanical loads, e.g. arterial wick. In such a case a short piece of the heat pipe profile is selected for mechanical qualification testing (sine, random vibration).
• An evaporator of a LH[’ or CI’L can be separately tested (sine, random vibration) to verify that mechanical requirements are met.
• Equally this can be true for a two-phase loop condenser, in particular for configurations where the condenser tubing is embedded into a structural panel.
Therefore the Standard does not specify at which model level vibration testing is performed. The supplier and customer are asked to agree on a logical qualification plan, which can include testing at higher than equipment level.
4.5 TPHTE acceptance principles
The acceptance process demonstrates that the already qualified product is free of workmanship errors and is ready for subsequent operational use.
Verification is performed by inspection and testing and includes:
• Material conformity (for example inspection of certificates, proof pressure, leak check)
• Inspection of dimensions and flatness
• Thermal performance check
The design of hardware submitted to the acceptance procedure has been previously qualified. However, some application driven design modifications can be accepted as long as the following qualification relevant design features are not compromised:
• Material selection and compatibility
• Pressunzed component
• Thermal performance
Some examples are given in Table 4-1.
It is good practice to perform a similarity analysis to determine that the hardware, submitted to the acceptance process. is of qualified design.
5.6 Qualification test programme
5.6.1 Number of qualification units
i The number of TPHTE units submitted to the qualification programme test units shall be in accordance with Figure 5-2 and Figure 5-3.
5.6.2 Test sequence
a. Equipment for which a full qualification programme is required as per Table 5-1 shall be verified by qualification testing according to the test sequence as defined in Figure 5-2 for HP and Figure 5-3 for CDL.
b. For an equipment where a delta qualification programme is required as per Table 5-1, the supplier shall derive from the test sequence of Figure 5-2 for HP and Figure 5-3 for CDL a reduced test sequence for delta qualification.
c. The delta qualification sequence shall be agreed with the customer.BS/EN 16603-31-02-2018 pdf download.
BS/EN 16603-31-02-2018 pdf download
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