%0 Journal Article
	%A D. Sufi Ahmadi and  B. Bagheri
	%D 2012
	%J International Journal of Chemical and Molecular Engineering
	%B World Academy of Science, Engineering and Technology
	%I Open Science Index 61, 2012
	%T Failure Analysis of Methanol Evaporator
	%U https://publications.waset.org/pdf/1488
	%V 61
	%X Thermal water hammer is a special type of water
hammer which rarely occurs in heat exchangers. In biphasic fluids, if
steam bubbles are surrounded by condensate, regarding lower
condensate temperature than steam, they will suddenly collapse. As a
result, the vacuum caused by an extreme change in volume lead to
movement of the condensates in all directions and their collision the
force produced by this collision leads to a severe stress in the pipe
wall. This phenomenon is a special type of water hammer. According
to fluid mechanics, this phenomenon is a particular type of transient
flows during which abrupt change of fluid leads to sudden pressure
change inside the tube. In this paper, the mechanism of abrupt failure
of 80 tubes of 481 tubes of a methanol heat exchanger is discussed.
Initially, due to excessive temperature differences between heat
transfer fluids and simultaneous failure of 80 tubes, thermal shock
was presupposed as the reason of failure. Deeper investigation on
cross-section of failed tubes showed that failure was, ductile type of
failure, so the first hypothesis was rejected. Further analysis and more
accurate experiments revealed that failure of tubes caused by thermal
water hammer. Finally, the causes of thermal water hammer and
various solutions to avoid such mechanism are discussed.
	%P 47 - 50