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- All Subjects: Thermodynamics
- Creators: Rykaczewski, Konrad
- Creators: Sayres, Scott
One of the ways in which we can improve the efficiency of heat exchangers is by applying ultrasonic energy to a heat exchanger. This research explores the possibility of introducing the external input of ultrasonic energy to increase the efficiency of the heat exchanger. This increase in efficiency can be estimated by calculating the parameters important for the characterization of a heat exchanger, which are effectiveness (ε) and overall heat transfer coefficient (U). These parameters are calculated for both the non-ultrasound and ultrasound conditions in the heat exchanger.
This a preliminary study of ultrasound and its effect on a conventional shell-and-coil heat exchanger. From the data obtained it can be inferred that the increase in effectiveness and overall heat transfer coefficient upon the application of ultrasound is 1% and 6.22% respectively.
The photodissociation of 1-bromobutane is explored using pump-probe spectroscopy and time-of-flight mass spectrometry. Fragments of bromobutane are constructed computationally and theoretical energies are calculated using Gaussian 16 software. It is determined that the dissociation of bromine from the parent molecule is the most observed fragmentation pathway arising from the excitation of the ground state parent molecule to a dissociative A state using two 400 nm, 3.1 eV pump photons. The dissociation energy of this pathway is 2.91 eV, leaving 3.3 eV of energy that is redistributed into the product fragments as vibrational energy. C4H9 has the highest relative intensity in the mass spectrum with a relative intensity of 1.00. It is followed by C2H5 and C2H4 at relative intensities of 0.73 and 0.29 respectively. Because of the negative correlation between C4H9 and these two fragments at positive time delays, it is concluded that most of these smaller molecules are formed from the further dissociation of the fragment C4H9 rather than any alternative pathways from the parent molecule. Thermodynamic analysis of these pathways has displayed the power of thermodynamic prediction as well as its limitations as it fails to consider kinetic limitations in dissociation reactions.