Rocket engine nozzle testing demands pitot probes capable of withstanding extreme pressures (up to 50MPa), requiring strict selection standards to ensure safety and data accuracy.5-Hole Pitotwelcome to click on the website to learn more!
Material strength is paramount. High-strength alloy steel (e.g., 40CrNiMoA) with a tensile strength >1200MPa is required, as lower-strength metals (e.g., 304 stainless steel) risk rupture. A test at 50MPa found 40CrNiMoA probes maintained integrity, while 316 stainless steel probes deformed, causing 10% pressure measurement error.
Wall thickness must be calculated with a safety factor of 2.5 (minimum 3mm for 50MPa), ensuring the probe can withstand pressure spikes during engine ignition. Finite element analysis (FEA) is used to verify thickness—one manufacturer rejected a batch with 2.5mm walls after FEA showed potential failure under 55MPa spikes.
Sealing technology is critical. Metal-to-metal cone seals (with 5° taper) prevent high-pressure gas leakage better than O-rings, which degrade under repeated pressure cycles. A rocket test facility found cone-sealed probes maintained pressure tightness for 50+ tests, compared to 10 tests for O-ring-sealed models.
Calibration must be performed at 120% of maximum pressure (60MPa) to ensure accuracy under operational loads. Probes with >0.5% error at 60MPa are rejected, as this translates to 3% error in nozzle thrust calculations.
These standards—high-strength materials, validated wall thickness, robust sealing, and high-pressure calibration—ensure pitot probes perform reliably in the extreme conditions of rocket engine nozzle testing.