A thesis, submitted to the Faculty of Engineering, University of the Witwa,t(m~~ rand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. -;;., Johannf,'"~l)Urg,. April'25, 1994 / A numerical' and experiruental. investig~tion ~£free~cylinder Stirling engines is repbited. Tllis work evolved from an attempt to de~,elop a palt.icular freecylinder Stirlingengineif::oncept, such that commerci~~lmanufa<:ture and application as .tll~power source for a wateP pu.mp could be. coosidered. Available desigI(~QoIs' 'were not. dirittly applicable .to the engine being ~onsi<:lered. .The linea'f altalysis technique (coupled ~ith segond orderheat tra~sferj,thermody: gamic and "loss ,analysis), dey-eloped and implernented as 18 computer, program~ e by nM Bercho~i~,z was therefore ext~nded to allow the simulation of free-cylinder engines. .The ,s~lut.ipn procedure (follows ~ more, gen~raHzed fqrm than that adopted by Betr~hovvttz.. As a ]."esrutsymbolic manipulation ..and solution of the equations was impracticaL However numericalroot map gen~rat!oIl and ,the simple pr?~uction of force vector ~iagrams q,llr,)ws useful design mformatlon babe obtained: ~0 n .. _ '. '.' .r, ' _ . ". ,' ' _ ' " -'~-::~_, ,; Experimentah~orkwas carried out .on-two very diff,~rent machines. 'A Sufi;' p,ower free-cylinder Stirling ,',engni,e,pr,ototype Jb,Q.elded,disapopi,,ntlllg.•res,u,lts, a~ ,.' '. _'!7.. . ,the engine did, not run: satisfactorily. However the. data gathered provides a useful check of the general applicability of t11-ecouple4 analysis, method. The second engine, a modified S,1lnpowerModel B-lO,Demonstra.~T 'yielded motion and pressure data .over a wide l'al1ge bf operating conditions} The effects o£" \I changes in parameters such as,thl:fcase-ground spring stiffness, di~placer spring stiffness, case mass, charge pressure, Qot-end temperature and load. were explored. Agreement between experlmentalreeults arid simula,tio\l:r~s41ts uS~flg the coupled analysis is reasonable, particularly when one consicI'ersoi;hewid~ range of operatin;g conditions over which the compari§on is made. " , , /.(""" ,0 ,