There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Magnetocaloric effect: From materials research to refrigeration devices

Review on sorption materials and technologies for heat pumps and thermal energy storage

Intensive literature review of condensation inside smooth and enhanced tubes

A comprehensive review on double pipe heat exchangers

For horizontal flow in the laminar flow regime, the interaction between natural and forced convection and the effect of the secondary flow induced by an unheated U-bend were considered in developing an empirical correlation for the nearly uniform heat flux condition. The correlation predicts the local peripheral average heat transfer coefficient with an absolute average deviation of 9.9%. In this article the mechanisms involved in laminar flow with the presence of a U-bend are explained. The realistic behavior of the correlation is illustrated. Also, a brief discussion of some of the existing correlations for laminar flow is presented. Four cases showing the practicality of using the correlation in the design of horizontal double-pipe heat exchangers are demonstrated.

Effect of mixed convection and u-bends on the design of double-pipe heat exchangers

An investigational absorption cycle was designed and constructed for research purposes. Nontraditional absorbent/refrigerant pairs were investigated and the selected working flu ids were aqueous ethylene glycole/water. The working fluids selected are safe, unlike the commercial absorbent/refrigerant pairs. This article discusses the challenges met in designing and constructing a research experimental absorption cycle, the unique designs of the various components, including instrumentation, data acquisition, and results of the experiments. With the current design of the absorber and desorber, the cycle has coefficients of performance of 0.67 and 1.2 for refrigeration and heat pump, respectively.

Ethylene Glycol/Water as Working Fluids for an Experimental Absorption Cycle

High heat fluxes are encountered in numerous applications, such as on the surfaces of hypersonic vehicles in flight, in fires, and within engines. The calibration of heat flux gauges may be performed in a dual cavity cylindrical blackbody. Insertion of instruments into the cavity disturbs the thermal equilibrium resulting in a transient calibration environment. To characterize the transient heat fluxes, experiments were performed on a dual cavity cylindrical blackbody at nominal temperatures varying from 800°C to 1900°C in increments of 100°C. The pre-insertion, steady state, axial temperature profile is compared experimentally and numerically. Detailed transient thermal models have been developed to simulate the heat flux calibration process at two extreme fluxes: the high flux is 1 MW/m 2 and the relatively low is 70 kW/m 2 . Based on experiments and numerical analysis, the optimum heat flux sensor insertion location as measured from the center partition was determined. The effect of convection (natural and forced) in the blackbody cavity during the insertion is calculated and found to be less than 2% at high temperatures but reaches much higher values at relatively lower temperatures. The transient models show the effect of inserting a heat flux gauge at room temperature on the thermal equilibrium of the blackbody at 1800°C and 800°C nominal temperatures. Also, heat flux sensor outputs are derived from computed sensor temperature distributions and compared with experimental results. The numerical heat flux agreed with the experimental results to within 5%, which indicates that the numerical models captured the transient thermal physics during the calibration. Based on numerical models and all experimental runs the heat transfer mechanisms are explained.

Experimental and Computational Characterization of High Heat Fluxes During Transient Blackbody Calibrations

The objective of the two-semester Capstone/senior design program, at Saint Martin’s Mechanical Engineering Department, is to prepare student- engineers for the workforce by having them participate fully on a design team to solve an open-ended real-world design problem. Students design, then build/assemble their project. For the senior design project students use their knowledge from all previous courses and creative improvisation. Additionally, socioeconomic and ethical issues are addressed as part of the design paradigm. Team work is emphasized. Problem recognition and statements, definition of the problem, constraints, alternative solutions and their evaluation, considerations of economics and manufacturing, scheduling, and meeting deadlines of the project are stressed. The distinctiveness of this program is the integration of students from the School of Business and the 'end-user' into the design team. The design project further hones oral and written communication skills of the team. This paper discusses the learning objectives and outcomes, structure of the class, organization of the senior design team and essential leadership positions, budget constraints, and other constraints on the project. Numerous projects were accomplished such as a recreational hovercraft, a water desalination system to be used in an orphanage in Tanzania, and an innovative instrumented heating, air conditioning bench top instructional experiment.

An Integrated Concept-to-Prototype Capstone Design Experience

The Senior Mechanical Engineering students at Saint Martin’s College designed and built a unique, safe air conditioning/refrigeration bench experimentation apparatus. The apparatus is currently used as laboratory equipment to support instruction in four thermal engineering courses. This system demonstrates the fundamentals of the refrigeration cycle and psychrometric properties of air, as well as some fundamental concepts in heat transfer, heat exchangers, and thermodynamics. The refrigeration cycle working fluid is R-134a. The cycle operates with pressures between 760 kPa and 210 kPa, and with temperatures between 44 °C and −7 °C with flow rate of 6.8 kg/h. The apparatus is equipped with an instrumentation package to monitor the psychrometric properties of the effected air inside the ductwork. In addition the instrumentation package contains instrumentation to monitor the working fluid properties via computerized data logging equipment. Technical details about the uniqueness of this design and operation are given in the article.Copyright © 2003 by ASME

Amanie N. Abdelmessih

Papers

Effect of mixed convection and u-bends on the design of double-pipe heat exchangers

Ethylene Glycol/Water as Working Fluids for an Experimental Absorption Cycle

Experimental and Computational Characterization of High Heat Fluxes During Transient Blackbody Calibrations

An Integrated Concept-to-Prototype Capstone Design Experience

Instrumented Air Conditioning Bench Experimental Apparatus