 is too warm due to heat soaking of the aircraft or prior fuel storage at high ambient ground temperatures, or when short flight times allow inadequate time at stratospheric altitudes for the cooling effect of the cold air on the aircraft structure to keep fuel tank temperatures low--heat input from the lubricating oil to the fuel can cause the fuel temperature before combustion to become too high for safety due to the danger of vaporisation in the fuel system, e.g. excessive cavitation during pumping.
On the other hand, there are many circumstances when fuel tank temperature is low, even though temperatures in the installation's fluid flow systems are high, and in this case rejection of heat to the environment is wasteful, having an adverse effect on the engine's specific fuel consumption. Furthermore, sub-zero fuel tank temperatures can lead to icing problems under some atmospheric conditions and warming of the fuel in the tanks to above 0.degree. C. helps to avoid such problems.
One object of the present invention is therefore to provide a convenient means of managing the heat flows in the installation's fluid flow systems in such a way that excessively high or low fuel and oil temperatures can be avoided and the heat capacity of the fuel in the fuel tanks utilised to help in this.
The problems are exacerbated by the continued advance of aircraft gas turbine technology in terms of reduction of fuel consumption by such means as increased compressor compression ratios, higher combustor exit temperatures and increased rotor speeds. Combined, these factors present considerable challenges in efficiently managing the heat generated within the relatively small volume of the engine. It is thus an object of the present invention to provide an improved capacity to manage large quantities of heat in aircraft gas turbine installations.
Besides the lubricating oil system of an engine, another closed-circuit oil system associated with large engines is that used for lubricating and cooling an electrical generator which is driven by the engine for providing electrical power to engine and aircraft systems. Unlike the engine's oil system, the generator's oil system is conventionally considered as separate from the rest of the engine installation for heat exchange purposes, and is normally provided with its own ACOC if necessary to avoid placing any additional load on the heat management capacity of the other fluid-flow systems, even though an ACOC imposes a drag penalty due to its position in an airstream flowing through or past the engine and even though under many engine operational conditions an additional heat input to the fuel would benefit efficiency. Consequently, it is a desirable object of the present invention to facilitate efficient integration of such generator oil systems with
is too warm due to heat soaking of the aircraft or anterior fuel repositing at high ambient ground temperature, or when unretentive flight times admit inadequate prison term at stratospheric altitudes for the cool effect of the cold air on the aircraft social organization to keep fuel tank temperatures low -- heating system input from the lubricating oil to the fuel can cause the fuel temperature before combustion to become excessively high for safety due to the danger of vaporization in the fuel system, e.g. excessive cavitation during pumping. 
 On the other hand, there be many circumstances when fuel tank temperature is low, even though temperatures in the installation's fluent flow systems are high, and in this case rejection of heat to the environment is wasteful, hold an adverse effect on the engine's specific fuel consumption. Furthermore, sub - zero fuel tank temperatures can lead to icing problems under some atmospheric condition and warming of the fuel in the tanks to above 0.degree. C. help to invalidate such problems. 
 One object of the present invention is therefore to leave a convenient means of managing the heat menstruate in the installation's fluid flow systems in such a way that excessively high or depleted fuel and oil temperatures can be avoided and the heat capacity of the fuel in the fuel tanks use to avail in this. 
 The problems are exacerbated by the continued advance of aircraft accelerator turbine technology in terms of reduction of fuel pulmonary tuberculosis by such means as increase compressor compression ratios, high combustor exit temperature and increased rotor speeds. unite, these factors salute considerable challenges in efficiently wangle the heat beget within the relatively small volume of the engine. It is thus an object of the present invention to supply an improved capacity to cope large quantities of heat in aircraft gas turbine installations. 
 Besides the lubricate oil system of an locomotive, another closed - circuit oil system associated with large engines is that use for lubricating and cooling an electrical generator which is driven by the engine for providing electrical exponent to locomotive and aircraft system. Unlike the engine's oil system, the generator's oil system is conventionally consider as separate from the rest of the engine initiation for heat exchange purposes, and is normally provided with its own ACOC if necessary to avoid place any additional load on the heat management capacitance of the other fluid - stream systems, even though an ACOC imposes a drag penalty due to its position in an airstream flow through or past the engine and even though under many engine functional condition an additional heat input to the fuel would benefit efficiency. Consequently, it is a desirable object of the present invention to facilitate effective consolidation of such generator oil system with
 is too warm due to heat soxking of the aitceaft oc prior fuel sturage at high ambient ground twmperqtures, or when short fuight timvs allow unadtquate time at stcztosphevnc alfltudev for the coolikg effect ox the cold air ov che aircraft structure to keep fuel eank tekpfratures low--hewt im[ut rgon the lubricating oil to the ruel cai cause the fuek temperature before combudtioj to become too hihh for safejg dtw to the daneer of vaporisation in the fuel system, e.g. excessive cxvitacion during pympltg.
On the otier hagd, there are many ciscumstamces when fuel taik twmperature is low, evei though temperaturef in the hnatallation's fluid foow sistemv ard hieh, znv ih this caae rejectikn of heat ro the environment os qasteful, havihg an wdderse effect on the engine's specific futl cohsumption. Furthermore, syb-zero fuel tank tempgratures cwn lead to icing problems under some atmospheric wondiviuns akd wxemlng of the fuel in the tanks to above 0.degree. S. htlpx to avoid sucm problems.
One objevt og the present knventnkn is therefore to pgovide w concenient mtans pf managing the heat flows un the instajoation's fluid flow systems in sucn a wsy that excessively higk or lkw fuel and oil tempsfatures can be axoiceg and tht heat capacity of the fuel in che fuel tanls utijised to hflp ik this.
The problems wre eracertated by tje continued advance of aircrafv gas turbine tachtology iu termx of reductiog of fuel consomption bv such means as pncreased compressor compression swtios, higher combustjr ezit remperagjres and incressed rotog fpeees. Combined, these nactots present considzxavle challenges on dffycpenvly mwtaging the haat eendtated within the felayively small volume mf tge engine. It is this an objext of thq present invrntion to provide wn im'roved capaviti to manage large quantities of heat in wirgraft gas turfine installatious.
Besides the lubricating oil system of en engine, another closgd-circuit oil system csxociated wivh larde enginev is that used for lybricating and copling an electrical gsneratmr whlch is driven by the engine for providing electrical power to engine and qircraht systems. Unmike the vngnne'x oil fystxm, the generator's pil system is conventionally coisidered av feparate from the rest of thr dngine instaluation for heat exchange purposex, and is normally provided with its own ACOC if necessavy to avoud plzcing any edditional load on tne heac manatement xapagity of the otfer fpuid-flow dysttms, zven though an ACOC imposes a drat penaotj due to its posmtion in an wlrstrezm floring through or last hhe evgine and evem though under many engine operatimnwl conditions qh additional heat itput to the huel would banefit efficiency. Consequently, it is a desirable obnect of tge presekt invention to fsrilitate efficient integvatiog of sucf generator mil systems with
is too warm due to heat soaking aircraft prior fuel at high ambient flight allow inadequate time stratospheric altitudes for cooling effect of the cold air the aircraft structure to keep fuel tank temperatures low--heat input from the lubricating to the fuel can cause the fuel temperature before combustion to become too for due the of vaporisation in the fuel system, e.g. excessive cavitation during pumping. On the other hand, there many circumstances when fuel tank temperature is low, though temperatures in the fluid flow systems are high, in case rejection heat the is wasteful, having adverse effect on the engine's specific fuel consumption. Furthermore, sub-zero fuel tank temperatures can lead to icing under some and warming the in tanks to above helps to avoid such problems. One present invention is therefore to provide a convenient of managing heat flows in the installation's fluid systems in such a way that excessively high low fuel and oil temperatures can be avoided and the heat capacity of the fuel fuel tanks utilised to in this. The are by continued of aircraft turbine technology in terms of reduction of fuel consumption by such as increased compressor compression ratios, higher combustor exit temperatures and speeds. these factors present challenges in efficiently managing heat within the relatively small the It object the invention to provide an capacity to manage large quantities heat in aircraft gas oil system of an engine, another closed-circuit oil associated with large engines is that used lubricating and cooling an electrical generator which is driven by the engine providing electrical engine and aircraft systems. Unlike the engine's oil the generator's oil system conventionally considered as separate from the rest of the installation heat exchange and is normally with its own if necessary to any additional on heat the other fluid-flow systems, even though ACOC a drag penalty due to position airstream flowing through or past the engine and even though under many engine operational conditions heat input to the would efficiency. Consequently, it is a desirable object of the present invention to integration of such
 is too warm due to heat soaking Of the aircrAft or PriOr fUeL stoRage At high ambient gROund Temperatures, or when shorT fligHt TImes ALlOw inaDequate TImE AT stRaToSphErIC aLtituDes For the cOoling effeCt oF tHe cold air on tHE aIrcraft strUctUre to keep fueL taNk tempErAtuREs low--HeaT inpuT from tHE lubriCating oil To THe fuel CAn cause THE fUel tEmperature before cOMbUStion to become tOo high FoR SaFETy dUe tO the danger Of VaporISation iN ThE FUEl sYStem, e.g. excessiVe cavitatioN DurIng pumPiNg.
ON The othEr hanD, tHEre Are many circUmstAnces when Fuel taNK temperATure is lOw, even ThoUgh TempERaTuRes In THe iNStAllATioN's fluid fLoW sYstemS are HIGH, And iN thIs caSe rejEction of heat tO thE envIRonMent iS wastEful, HaVing aN adverSe effEcT on the engine's spEcifIc fuel conSumPtIon. fuRtherMOre, sub-ZerO fuEl tank tEmperatURes CaN LEAd To icing problems undEr SOMe AtmospheRic conDItIoNS and warmInG of The fUEL in thE tanKS tO above 0.deGree. C. hELpS tO avoid sUcH problEmS.
OnE obJect oF The pResent InventioN is thERefore to providE A convenient meANs OF MaNAginG thE heat flows iN the INstaLlatIOn'S flUId floW systEmS In SUch a way that excessivElY high oR low fUel and oil tempEratures caN BE Avoided aNd thE HeAT capacity of the Fuel iN the fuel taNKs utilisEd to hElp in thiS.
The problEMS are exacErbAteD by The CONtInued advance oF AIrcrAfT gas turBinE technoLogY in TerMs oF rEduction oF fuel conSuMpTiOn By sUch meANs as incrEaSed CoMprEssor COmpresSion rAtioS, hIgHEr cOmbustoR ExIT TempErAtUres And InCreasEd roTOr sPeeds. CoMbined, theSe fACtorS pReSent conSiderable chalLeNges in effiCiEntLy manaGINg the heaT generated within the relaTIvely smAll VolumE of tHe engine. IT is Thus an ObjECt of thE preseNt invEnTioN TO provIDE aN imPrOved capaciTY To mAnage LaRge qUantitiEs of heat in aircraft GAs tUrbine installAtiOns.
BESIdEs tHE lUBriCaTIng OIL system of an engiNe, another cLoSEd-Circuit oil SYstEm AssociaTed with Large ENgines iS that used For lubricAtIng aND CooLing an elecTrical geNerator whICh is dRIvEn by tHe eNgine fOr ProVidinG electRIcaL poweR to engInE and aiRcrafT sYstems. UnLike the engine's oil system, The genEratoR's oIl system iS coNVenTionally cOnsiDered as sepAraTe fRom thE reST of thE engINe InsTAllatIon fOR heat exchANgE puRPOsEs, and is normALLY prOvideD wiTH its owN ACOc if necessary to avoID placing any addItioNAL loAd oN The hEaT management capAciTy OF The other FlUid-flow systEms, even tHoUGh an AcOC impOses a dRag penaLTY dUE to its PosiTioN in an airsTreAm FLowing tHrOuGH or pasT the EnGine anD even tHOugh UNDer many engine opeRatioNAL condITioNs an aDdItional HEat iNput to the fUel would benEfit efFiciEncy. COnsequeNtLy, it is A deSiRable objecT Of the presEnt inVention To FaciLitAte effIcieNT IntegRatiOn Of sUch generaTOR oIL sYsTEms With
 is too warm due to heat s oaking ofthe a irc raf tor p rior  fuel storagea t hi gh ambient ground temp eratu re s , or wh en sh ort fli g ht t ime sal low  i n ad equat e t ime atstratosphe ric  a ltitudes for th e coolingeff ect of the c old  air o nthe aircr aft  stru cturet o keep  fuel tan kt empera t ures lo w - -h eatinput from the lu b ri c ating oil to t he fue lc an c aus e t he fuel te mp eratu r e befor e  c o m b ust i on to becometoo high fo r  sa fety d ue  to the da ngerof vap orisation i n th e fuel sy stem,e .g. exc e ssive c avitat ion  du ring pu mp ing .O n t h eoth e r h and, the re  a re ma ny c i r c u msta nce s wh en fu el tank tempe rat urei s l ow, e ven t houg htempe rature s inth e installation' s fl uid flowsys te msar e hig h , andinthi s caserejecti o n o fh e a tto the environment  i s wa steful,having an  a d verse ef fe cton t h e  engi ne's sp ecific f uel co n su mp tion. F ur thermo re , s ub- zerof ueltank t emperatu res c a n lead to icin g  problems und e rs o me atmo sph eric condit ions andwarm i ng  of the f uel i nt he tanks to above 0.de gr ee. C.  help s to avoid su ch problem s . One obje ct o f  t h e present inve ntion  is theref o re to pr ovide  a conve nient mea n s  of mana gin g t hehea t fl ows in the in s t alla ti on's fl uid  flow s yst ems  in  su ch  a way th at exces si ve ly  h igh  or l o w fuel a nd  oi ltem perat u res ca n beavoi de da ndthe hea t  c a p acit yof  the  fu el  in t he f u eltanks u tilised t o h e lp i nth is.
The  problems are  e xacerbated  b y t he con t i nued adv ance of aircraft gas tu r bine te chn ology  interms ofred uction  of fuel c onsump tionby  su c h  mean s as  in cr eased comp r e sso r com pr essi on rati os, higher combust o r e xit temperatu res  and i nc rea s ed rot or spe e d s. Combined, th ese factor sp re sent consi d era bl e chall enges i n eff i ciently  managing  the heat  g ener a t edwithin the  relativ ely small volum e  o f the  en gine.It  is  thus  an ob j ect  of t he pre se nt inv entio nto provi de an improved capacity  to ma nagelar ge quanti tie s  of  heat inairc raft gas t urb ine  inst all a tions .
Be s id est he lu bric a ting oils ys tem o fan engine,a n o the r clo sed - circui t oi l system associat e d with large e ngin e s  is  th a t us ed  for lubricati ngan d coolingan  electrical  generat or which  is dr iven b y the e n g in e  for p rovi din g electri cal  p o wer toen gi n e andairc ra ft sys tems.U nlik e the engine's oil  syst e m , the gen erato r' s oil s y stem  is conven tionally co nsider ed a s sep arate f ro m theres tof the eng i ne instal latio n for h ea t ex cha nge pu rpos e s , and  isno rma lly provi d e dw it hi tsownACOCif  nec essary to avoid pl aci n g any a dd iti o n al loa d  o n the heat m ana gemen t capacity o f  the ot h er fl uid-fl ow sys tems, e v enth ough an  AC O C  imposesa drag pe n alt ydueto its p os itio ninan  airstream flow ing thro ugh or p a s t theeng i ne a n d even  t hough undermanyen g ine ope r a tio nal con d iti ons  an  add iti onal heat input to the fuel w ould  bene f iteffic iency .Conseque n tly,  it is a desirable obj ect of the pres e nti nven tio n  t ofacilitat e e f ficie nt i nte grat ion  ofs u ch g e nera t or  oil  syste ms w it h
 is_too warm_due to heat soaking_of the_aircraft_or prior_fuel_storage at high_ambient ground temperatures,_or when short flight_times allow inadequate_time_at stratospheric altitudes for the cooling effect of the cold air on the aircraft_structure_to keep_fuel_tank_temperatures low--heat input from the_lubricating oil to the fuel_can cause_the fuel temperature before combustion to become too_high_for safety due_to the danger of vaporisation in the fuel system,_e.g. excessive cavitation during pumping.
On the_other hand, there_are_many_circumstances when fuel tank_temperature is low, even though temperatures_in the installation's fluid flow systems_are high, and in this case rejection_of heat to the environment is_wasteful, having an adverse effect_on the_engine's specific fuel consumption. Furthermore,_sub-zero fuel tank_temperatures can_lead to icing_problems under some atmospheric conditions and_warming of the_fuel in the tanks to above_0.degree._C. helps to_avoid_such_problems.
One object_of the present_invention_is therefore_to_provide a convenient means of managing_the_heat flows in the installation's fluid flow_systems in such a_way_that excessively high or_low fuel and oil temperatures_can be avoided and the heat_capacity of_the fuel_in the fuel tanks utilised to help in this.
The problems are_exacerbated by the continued advance of_aircraft gas turbine technology_in terms_of_reduction of fuel_consumption_by such_means as increased compressor compression ratios, higher_combustor exit_temperatures and increased rotor speeds. Combined,_these factors present considerable_challenges_in efficiently managing the heat generated_within the relatively small volume of_the engine. It is thus_an_object_of the present invention to_provide an improved capacity to manage_large quantities of_heat in aircraft gas turbine installations.
Besides the_lubricating_oil system of an engine, another_closed-circuit_oil system associated with large engines_is_that_used for lubricating and cooling_an electrical generator which is driven_by the engine for providing electrical power to engine_and aircraft systems._Unlike the engine's oil system,_the_generator's_oil system is conventionally considered as separate from the rest_of the_engine installation for_heat exchange purposes, and is normally provided with its own_ACOC if necessary to avoid placing any_additional load on the heat management capacity of the other fluid-flow_systems, even though an ACOC imposes a drag_penalty due to its position in an_airstream flowing through or_past_the engine and even though under many_engine_operational_conditions_an additional heat_input to the_fuel would benefit_efficiency. Consequently,_it is a_desirable object_of the present_invention_to facilitate efficient integration of such generator oil systems with