Re-Entry Simulation

Re-Entry Simulation Chamber

The aim of the test facil­ity is the simu­la­tion the mech­an­ical, thermal and atmo­spheric loads on crit­ical parts during the re-entry phase of reusable launch­ers or space­craft for plan­et­ary explor­a­tion. The main part of the device is a completely water cooled stain­less steel vacuum cham­ber oper­at­ing at a pres­sure of better than 10-6 mbar or with increas­ing gas pres­sures of N2, H2, O2 up to atmo­spheric pres­sure. The control of the gas envir­on­ment is performed by means of a Pfeiffer valve EVR 116 together with a Pfeiffer RVC 300 control unit.

A high-perform­ance self-adjust­ing induct­ive heat­ing system with an output power of 30 kW (Plustherm TN 30) is imple­men­ted to achieve temper­at­ures up to 2500 °C with a heat­ing rate of more than 50 K/s (depend­ing on mater­ial). Various induc­tion coils are avail­able for a multi­tude of sample shapes and dimen­sions to ensure optimum induct­ive coup­ling of the heat­ing power. Customer-specific solu­tions are being manu­fac­tured in house. Temperature meas­ure­ments are performed with ther­mo­couples. with a quotient pyro­meter Impac ISQ 10 LO (range 300° to 2500 °C), or a combin­a­tion thereof. Special Infrasil windows in the obser­va­tion ports guar­an­tee an accur­ate pyro­met­rical determ­in­a­tion of the sample surface.

re_entry_1Applications are thermal shock test­ing, thermal cycling and gas cycling tests, thermo-mech­an­ical tests and combin­a­tions thereof, e.g. sinter­ing or hot-pressing.

Applications are thermal shock test­ing, thermal cycling and gas cycling tests, thermo-mech­an­ical tests and combin­a­tions thereof, e.g. sinter­ing or hot-pressing.

The vacuum cham­ber is placed in a servo-hydraulic test machine LF 70S from walter & bai. Dynamic loads of up to 70 kN with a frequency of up to 70 Hz and a vari­ety of signal shape can be applied on the test samples. Both hot and cold grip­ping systems are avail­able. Strain meas­ure­ments are performed either by strain gauge or by a non-contact­ing system.

All func­tions of the device are completely micro­com­puter-controlled, and the highly soph­ist­ic­ated control soft­ware allows a conveni­ent and reli­able acquis­i­tion of all relev­ant process parameters.

Technical Data Summary
  • Diameter 600 mm, usable sample height 500 mm (without exten­sion flanges)
  • Heating power 30 kW, frequency 20<>150 kHz self-optimising
  • Customer specific induc­tion coils for crit­ical applic­a­tions on request
  • Fully compu­ter­ised temper­at­ure and heat­ing control
  • Temperature meas­ure­ment by pyro­met­ers or thermocouples
  • Vacuum better than 10 -6 mbar
  • Automatic pres­sure and atmo­sphere compos­i­tion control
  • Mechanical loads up to 70 kN, static or with a frequency up to 70 Hz (sinus, rect­an­gu­lar, triangle, ...)
  • All relev­ant process para­met­ers controlled and recor­ded by microcomputer
Laser speckle extensometer

re_entry_2The re-entry cham­ber was equiped recently with a high resol­u­tion laser speckle extens­o­meter. The extens­o­meter comprises a PC-based video processor, which continu­ally meas­ures the displace­ment of two speckle patterns, recor­ded by two video cameras and two lasers. The two displace­ments are conver­ted into strain signal, which is send to a control and eval­u­ation system for data handling.

The advant­ages of a contact free extens­o­meter are:

  • No speci­men preparation
  • No Moving part, main­ten­ance free
  • Two dimen­sion­al­ity
  • Arbitrary initial gauge lengths: 0<>250mm
  • Testing temper­at­ures up to 1600°C
  • Measuring of E-moduli and break­ing strains with a single system