ERG Aerospace manufactures heat sinks that can be used in various fields. The current problem that they are facing is the inability to test their heat sinks under the specific environments that the heat sinks are intended. The ERG heat sink test bench project will result in a product that can test heat sinks quickly and efficiently. The product will be able to monitor and manipulate the temperature and pressure inside the testing environment and allow for different shapes and sizes of heat sinks to be tested. Overall the ERG heat sink test bench will reduce the cost of outsourced heat sink testing, and allow for accurate and efficient data to be collected for any heat sink of the company’s choosing.
Proof of Concept
ERG is a small company primarily focused on Aerospace technology although their product, Duocell, can be applied to many other fields. Duocell is a form of metal foam that is produced in a unique way that allows for ERG to be a major competitor to other metal foam manufacturers. The process that ERG uses is generally faster, and yields a higher quality product than competing companies in the metal foam market. The design team has researched the aerospace and metal foam industry to understand the market so that the ERG test bench project will be successful in meeting its desired specifications.
Heat sink solutions design team is working with ERG Aerospace in order to create a heat sink testing vessel. The team has come up with a design that will be able to test the heat sinks ability to withstand different temperatures, pressures, and fluid flow. In order to prove that the testing apparatus will be able to support all of the testing requirements, the team performed multiple analysis’ using Solidworks, Ansys, and hand calculations.
In order to test for pressure and vacuum differences, the team used finite element analysis on Solidworks. The team created a design of the heat sink test bench with specific initial conditions and used a static study in order to test how a drastic change in pressure would affect the vessel. A Von Mises stress test and a displacement test were performed on multiple different versions of the teams design to decide on the the strongest materials and connections. The results of these two studies show the vessels ability to hold the pressure with little deflection and withstand the vacuum pressure of 5 psi and other specifications discussed in the Product Design Specifications (PDS).
A program called Ansys was used in order to test the effect of temperature differences within the testing vessel. The PDS states that the vessel must be able to hold a temperature of 80℉ inside the testing environment for the elapsed time of each test. The team set the conditions of the outside environment to mimic a server room and imported a model from Solidworks. A model was redesigned without a lid in order to observe heat transfer through the walls of the vessel. Initial requirements such as Acrylic material, 80℉ internal temperature, and 60℉-75℉ external temperature were set and a mesh was applied. Free convection on the inside and the outside of the vessel and heat flux was measured using a Steady-State thermal analysis. This simulation provided an analysis to prove that the material chosen for the test bench will provide minimal thermal conductivity and allow the team to calculate the amount of heat needed maintain the 80℉ initial temperature.
After analyzing the vessel for all testing requirements, the team has proved that their design will hold up to the specifications described in the PDS. These concepts will be applicable for real-world applications in the testing heat sinks of different sizes and forms.
Figure 1: The concept overview shows the visual break down of the Heat Sink Test Bench chosen concept.
Final Design Description
The final design of the ERG heat sink test bench consists of six, one inch thick acrylic panels assembled to form a rectangular prism enclosure as shown in the figures found below. There are two, 18”x18” panels with a 0.5”x1” notch along the entire perimetric edge of the face of the panels. These will be used as the bottom and lid of the enclosure. The vertical walls of the enclosure consists of two, 12”x18” panels and two, 12”x17” panels. All of these panels will have a 0.5”x0.5” notch along their 12” edges. The enclosure will have internal dimensions of 11”x16”x16” and exterior dimensions of 13”x18”x18”. The panels will be attached to each other using a combination of weld-on 4 and silicone. The weld-on will provide a strong, structural bond while the silicone will be applied afterward for sealing purposes. Four ¼” diameter holes will be drilled into the lid panel spaced at 3”x3” from the corners of the panel. One of the holes will be used for piping which will allow to pull vacuum inside of the enclosure. It consists of a four way cross pipe fitting with a pressure relief valve attached to one end, a pressure gauge to another, piping to the vacuum pump on another, and the final one screwed into the lid itself. The other 3 holes will be used as wire feedthroughs for the thermocouples and power cables which will be used to power the heat source and heating element. The enclosure is designed to withstand the pressures/stresses of 0.7 psi (absolute, -14 psi gauge pressure equivalent) with a FOS of at least three. Additionally, the enclosure should be insulating enough so that less than 1˚ F of heat is lost to the environment over a time period of 5 minutes under expected operating conditions of 80˚F internal temperature and 65˚F external temperature.
This product will allow ERG to test the heat sinks they manufacture in house and compare their performances, under the same conditions, to heat sinks currently on the market which are being implemented in similar applications/uses. In the past ERG has had to outsource the testing of their heat sinks. This process has grown expensive and has had other undesired outcomes/consequences such as no control over the measurements collected during the tests as well as delays in receiving results back. The heat sink test bench was designed to the specific needs and requirements of ERG, allowing them more control over the exact testing procedures and methods as well as the measurements collected. One important feature of the product is the manipulatable environment, in terms of pressure and temperature, which will allow for the testing of heat sinks in the exact conditions in which they will be used. This allows ERG to more accurately predict their heat sink performance in specific applications where they will be subjected to known conditions. Additionally, ERG will be able to advertise to potential customers the increased performance they will achieve when using their heat sinks as opposed to those from other manufacturers. Finally, the heat sink test bench will allow ERG to save money in the long run and will also provide them with immediate results when testing new heat sinks which will allow for more efficient product design/redesign.
3-Dimensional SolidWorks Models
Below are three, 3-dimensional models created in SolidWorks depicting the final assembly of the product. They include one general/overall assembly and two sub-assembly models. The sub-assembly models are used to show the assembly of the product in greater detail where deemed necessary for full understanding of the product from the reader.
The ERG Heat Sink Test Bench consists of a vacuum chamber made out of acrylic panels, a vacuum valve system, a heat source operated by a power supply, and a heat lamp operated by a controller. The acrylic panels were manufactured by Tripp Plastics. Tripp Plastics cut the acrylic sheets to the appropriate dimensions and created the notches on all sides so that each piece fits together. Tripp Plastics also machined all of the surfaces to create a smooth finish appropriate for solvent bonding.
The acrylic panels were then bonded and clamped by using weld on 4. The panels were supported by c-clamps until the curing process was completed.
After curing was completed, silicon was applied to all internal and external connections to create an air-tight seal. Once the silicon was completely cured, the gasket making process was initialized.
To make the gasket for the vacuum chamber lid, food coloring and silicon were mixed together and then rolled into corn starch. This mixture creates an anti-stick rubber similar to putty that can be molded for 15 minutes before setting. The gasket material was placed on the edges that would be in contact between the lid and the base of the chamber and left for the rubber to cure completely. Once the curing process was complete, the rubber gasket was adhered to the lid with silicon.
After the vacuum chamber gasket was finished, a 1/4” NPT threaded hole was created on the lid of the chamber so that the vacuum system could be installed. The vacuum system was assembled by using two pressure relief valves, a pressure gage, and a cross connector with male to male connections between each component. One pressure relief valve was fitted with a quick connect nipple to allow for the vacuum pump to be connected. All connections in the pressure system was sealed with plumbers’ tape to ensure an air-tight seal.
After the pressure system was installed, a steel table was manufactured by welding together square tube, sheet metal, and casters for the base. All thread rods were secured to the top layer of sheet metal so that the lid supports could be installed. Then two pieces of angle iron were cut to be used as the lid support beams.
After the table was manufactured, five 3/16” holes were drilled into the side of the acrylic walls so that five 10 gage wire feedthroughs could be placed into each hole. The wire feedthroughs were secured inside of the holes with silicon and a spade fitting were crimped to each end of the wires to allow for quick connections to be made.
The final step in manufacturing the test bench involved inserting each of the internal components inside of the testing chamber. The heat lamp, controller, and thermometer were fastened to the inside walls with command strips. The thermocouple for the controller was secured to the opposite side of the chamber with tape. The heat source was then placed inside of the chamber. The heat source and controller were connected to the wire feedthroughs. The controller wires were then connected to a plug, and the heat source wires were connected to the power supply unit on the outside of the chamber.
The heat sink test bench full assembly is shown below.
Testing and Results
Meet the Team
Damian Whittemore is a 4th year mechanical engineering student at UNR. He was born in Truckee, California but was raised in Portola, California. He participated in 4-H for six years and eventually became a 4-H leader for the swine showmanship branch of the club. Beginning his engineering career, he received an internship opportunity from ERG Aerospace and a job offer upon graduation. During his internship he had to use critical thinking and the engineering design process on multiple occasions to modify two major company processes to increase efficiency. During his academic career, Damian has developed his problem solving and process management skills which proved to be useful in his internship. Damian’s current goals are to finish college with a 3.3 GPA and upon graduation he plans to work at ERG Aerospace to develop his job experience and move up in the company.
Freddy Sosa is currently completing his senior year of his Mechanical Engineering degree at UNR. He was born in Providence, Rhode Island but was raised in Las Vegas, Nevada. He graduated highschool with an Advanced Honors diploma and was awarded the Presidential Scholarship by UNR to go there for his collegiate career. During his sophomore year at UNR, he obtained an internship with Granite Construction company in their Sparks, Nevada office for the summer of 2017. At his internship Freddy applied and further developed his critical thinking and problem-solving skills to help company engineers and project managers estimate, bid, build, and complete construction jobs. At the end of that summer, Freddy was invited to continue working for the company during the school year as well as the following summer. Freddy’s current goals are to graduate from UNR in Spring, 2019 with a 3.5 GPA and continue to work for Granite thereafter to further develop his skills and strengthen his job experiences.
Ty Finegan is a senior mechanical engineering student at the University of Nevada, Reno. He is originally from Turlock, California where he spent all of his primary schooling. While attending UNR, Ty has improved his problem solving and critical thinking skills through working on school work. During his spring semester, he received an internship with a HVAC engineering design consultant company, CR Engineering, where he continues to work. While working at the company, he has gained experience in 2D CAD where he has aided in the design and drafting of commercial HVAC systems. Working at CR has tested the academic knowledge by displaying the real world applications of his studies and presented restrictions that are present outside of school in the means of codes. Ty’s goals to graduate Spring of 2019 with a 3.2 GPA and find a job in the engineering field of energy or manufacturing.
Daniel McCready is a senior in the mechanical engineering department at the University of Nevada, Reno. Dan was raised in the town of Loomis, California and moved to Reno, Nevada to attend UNR. During his time studying Engineering, Dan has achieved an academic scholarship based on his GPA. While working in a university research lab, Dan as well as two doctorate candidates created a new way to process and analyze cellulose samples. Dan was tasked with the responsibility to determine the angles needed when slicing tree sample cores as to not affect the samples and then create a machine which was able to do so. With this task, the use of analytical techniques were required to help define the problem and solutions necessary to create the machine. Over the summer Dan was recognized at the largest paleoclimatology conference in the world for the process he helped create. Dan has goals to graduate from UNR in spring, 2019 with a GPA of 3.25. Dan has the goals of beginning his career in the engineering industry in the Reno or Sacramento area.
Julia Stueve is a senior at the University of Nevada, Reno and is concluding her last year in the mechanical engineering program. Julia was born in Las Vegas, Nevada and moved to Reno, Nevada to continue pursuing her academic career. During her time at the university, she has been challenged to work with fellow engineers of different specialties to create or improve upon several projects. Her most challenging engineering project to date has been to create her own company as an entrepreneur and pitch it to angel investors in an attempt to receive funding. This challenged her to do extensive amounts of research and analytical thinking as well as design a stable product and convincing business model. Aside from school, Julia was offered an internship at RHP Mechanical Systems during her junior year and has been guaranteed a job with the company after graduation. During her internship, Julia has been responsible for drafting projects using CAD, project management, along with communicating and meeting with clients, vendors, and fellow business partners. She has also joined ASHRAE in order to assist her in continuing her education after college. Outside of engineering, Julia was elected Vice President of Programming for her sorority. Her responsibilities inside and outside of school have improved her analytical thinking, problem solving, attention to detail, and time management skills. After graduation, Julia plans on choosing a specialty and continuing her education to get her Master’s Degree with the help of RHP.