In the context of increasing the efficiency of alternative energy sources applications, Stirling engines attracted researchers to study the engine performance since it is an external heat addition engine that can work with renewable heat resources or with waste heat from plants working with fossil fuels with an efficiency equivalent to Carnot efficiency. Additional advantages exist, such as quiet operation and lower emissions than internal combustion engines. The regenerator is an essential part of Stirling engine as it plays a vital role in its operation especially in the two isochoric heat transfer processes representing a heat barrier and transferring heat to the fluid in the first half of the cycle and transferring heat from the fluid in the second half of the cycle. In the last two decades, the development of CFD methods made it possible to study transport phenomena without the need for costly experimental methods and can give more detailed information about the effects of geometrical parameters than the theoretical or analytical methods. The purpose of this study is to develop a model for an alpha type Stirling engine and using the advantage of geometrical representation in CFD models to study the effect of changing regenerator geometry on engine performance. Validation of the model against results in the literature was performed. Results showed that the dimensionless work parameter was 0.011 for the novel geometry while it was 0.065 for the original regenerator, decreasing the engine speed increased the dimensionless work parameter to 0.018, effects of changing apex angle and wall thickness on the dimensionless parameter were investigated.

‫البيئية‬ ‫العلوم‬ ‫مجلة‬ ‫اس‬ ‫الدر‬ ‫معهد‬ ‫البيئية‬ ‫البحوث‬ ‫و‬ ‫ات‬ -‫شمس‬ ‫عين‬ ‫جامعة‬ ‫المجلد‬ ‫األ‬ ‫و‬ ‫ابع‬ ‫الر‬ ‫ديسمبر‬ ‫الثاني،‬ ‫الجزء‬ ‫بعون،‬ ‫ر‬ 8102 391 ‫بال‬ ‫الوعى‬ ‫تنمية‬ ‫فى‬ ‫االعالم‬ ‫وسائل‬ ‫بعض‬ ‫دور‬ ‫لدى‬ ‫االخضر‬ ‫تسويق‬ ‫المصرى‬ ‫الجمهور‬ -‫وميدانية‬ ‫تحليلية‬ ‫دراسة‬ [ 51 ] ‫صبري‬ ‫ميرهام‬ ‫أمين‬ ‫صبري‬ ‫ميرهام‬ ‫أمين‬ ‫وآخرون‬ ‫المجلد‬ ‫األ‬ ‫و‬ ‫ابع‬ ‫الر‬ ‫ديسمبر‬ ‫الثاني،‬ ‫الجزء‬ ‫بعون،‬ ‫ر‬ 8102 428mentioned in green marketing, in favor of the higher education level individuals.  Motional effects in the advs. comes in the first rank, followed by "sound", then "abundance in environmental information presented in the advs." In the third rank, followed by "designing the advs." And finally the "emergence of famous persons".  The most important mass media means viewed by a large number of people is television followed by the facebook on websites.  The study sample counts on television because of the abundance of environmental information it presents concerning the green products.  The study is summed up of some recommendations as follows:  The necessity for increasing companies' concern in green products marketing or environmentally friendly forms of advertising that attract viewers such as advertising, singing , acting and develop to increase the persuasion of viewers and urges them to change their behavior towards them.