COST EFFECTIVE USE OF LIQUID NITROGEN IN CRYOGENIC WIND TUN-NELS.

PART 1 OF CRYOLAB'S PHASE I WORK DEALT WITH RELIQUEFACTION OF NITROGEN FROM A CRYOGENIC WIND TUNNEL. IT WAS DETERMINEDTHAT A NITROGEN RELIQUIDFIER COULD RECOVER FROM 12 TO 19% OF THE LIQUID NITROGEN CONSUMED IN A CRYOGENIC WIND TUNNEL WITH NO NET EXTERNAL POWER REQUIREMENT. KEY ELEMENT IN THE LIQUID NITROGEN RECOVERY SYSTEM IS AN INNOVATIVE POSITIVE DISPLACEMENT WET EXPANDER WHICH HANDLES FULL FLOW OF COLD NITROGEN EXHAUSTING FROM THE TUNNEL. PROPOSED PHASE II WORKCONSISTS OF DESIGN AND DEVELOPMENT OF A 0.65 KG/S THROUGH- PUT (50 CFM AT EXPANDER INLET) SYSTEM FOR TESTING AT CRYOLABUNDER SIMULATED WIND TUNNEL CONDITIONS. MAJOR PARTS OF THE PROPOSED WORK INCLUDE EXPANDER DESIGN AND DEVELOPMENT, SYSTEMS ANALYSIS, DESIGN AND FABRICATION OF CRYOGENIC COM- PONENTS, INSTALLATION AND TEST AT CRYOLAB AND FINAL ANALYSESAND REPORT PREPARATION. PART 2 OF PHASE I ADDRESSED THE LIQUID NITROGEN SUPPLY SYS- TEM FOR THE 0.3 M WIND TUNNEL AT NASA LANGLEY RESEARCH CTR. RESULTS INCLUDED SPECIFIC HARDWARE AND PROCEDURAL RECOMMEDA-TIONS TO REDUCE LIQUID NITROGEN LOSSES, IMPROVE OPERATIONAL CONTROL AND LOWER RISKS OF PERSONNEL EXPOSE TO LIQUID AND GASEOUS NITROGEN. RECOMMENDATIONS WERE BACKED BY PRELIM- INARY HARDWARE DESIGN AND COST ESTIMATES PERMITTING DIREC IMPLEMATATION WITHOUT ADDITIONAL STUDY OR DEVELOPMENT. WORKIN THIS CATEGORY IS NOT INCLUDED IN PHASE II.