ENGINEERING
ENGINEERING
kalepatech
Engineering and Design for a Better World
kalepatech
SustainabilityConsulting and Strategy
ELECTRONIC CHASSIS THERMAL DESIGNCOLD PLATE MODEL FOR COOLING POWER MOSFETS
Baseline analysis Surface Tmax = 78.9C (matches well with test data)
Maximum Ferrite Temperature Vary Copper Plate Thickness
0.080
0.125
0.094
0.100
65
66
67
68
69
70
71
72
73
74
75
0.07 0.08 0.09 0.1 0.11 0.12 0.13
Copper Thickness (in)
Maxim
um
Ferr
ite T
em
pera
ture
(degC)
Final design analysis for cooling MOSFETS and Tmax,MOSFET = 65.3C and Tmax,DIODE= 72.4C.
A parametric study of cooling the power transformers to evaluate heat sink geometries, fluid cooling and speed options.
kalepatech
Engineering and Design for a Better World
kalepatech
SustainabilityConsulting and Strategy
SOLID STATE ELECTRONICS EVALUATIONRESEARCH, ANALYSIS AND CONCEPT GENERATIONThermal management for high powered solid state devices is important in increasing the life of the device. Thermal analysis generated models and alternative layouts to minimize junction temperature and maximize duty cycle using only natural convection. Two-dimensional hand calculations, material selection evaluation and layout alternatives were evaluated
Two analytical studies evaluated layout configurations and designs.
. Thermal FEA Studies
Natural Convection CFD Studies
Through Thickness Temperature DistributionCurrent Design (2D Paper Study Model)
96.784
98.37996.841
99.353
127.853
50
62
74
86
98
110
122
134
146
158
170
0 0.5 1 1.5 2 2.5 3 3.5
Thickness (in)
Tem
per
atu
re (°
C)
Heat Sink
Base
Spreader
Substrate
LED package
kalepatech
Engineering and Design for a Better World
kalepatech
SustainabilityConsulting and Strategy
20,000 CFM WINDTUNNEL DESIGN
Lytron Inc designs industrial heat management solutions. A 30kW oil to air heat exchanger, required a new wind tunnel for test and validation. As laboratory and test equipment manager, I designed sensor and control system, specified the heating and cooling system and aided in the wind tunnel design.
The sensor system included:
2 Venturi Tubes with 0.25% accuracy
3 differential pressure gauges
Four absolute pressure gauges
18 thermocouples
Two Coriolis liquid flow meters
The sensors system was integrated with a data
acquisition system run on a LabVIEW platform.
User interface design and test stand validation
achieved a 98% heat transfer balance during
transients and near perfect balances during
steady state.
A full press release about the wind tunnel design
can be viewed at :
www.lytron.de/about/press_releases/2006_02_wind_tunnel.aspx
kalepatech
Engineering and Design for a Better World
kalepatech
SustainabilityConsulting and Strategy
INFLATABLE DOWNHOLE SEAL DESIGN DIVISION OF FORMATION EVALUATION, RAPID RESPONSE
New inflation packer elements were developed to withstand temperatures above 285°Fin mud. Previous attempts to extend operating range were unsuccessful. I led this project as an active collaboration between two suppliers and two product centers to develop the an improved packer design.
Project Objectives:
Increase temperature rating in stages.
Develop reliable packers elements.
Improve supplier performance
Improve reliability and performance
Technical challenges addressed:
Reduce elastomer extrusion
Decrease the degree of elastomer degradation
Improve the compatibility of elastomers with mud
Prevent outer bladder separation
Prevent plastic deformation of mechanical support
kalepatech
Engineering and Design for a Better World
kalepatech
SustainabilityConsulting and Strategy
HIGH PRESSURE CHAMBER EVALUATIONDIVISION OF FORMATION EVALUATION
Electromechanical tools are used to characterize oil wells after drilling. The Modular Reservoir Formation Tester (MDT) is a reservoir pressure and sampling tool that analyzes oil well fluid properties such as pressure.
An effort to increase pressure ratings of sample chambers from 20ksi to 30ksi resulted changing the material and design. The project produced technical recommendations and alternative designs to determine the appropriate pressure rating of active and future chambers.
Pressure test results, failure analysis and material studies revealed Titanium Beta C sample chambers were suitable for lower pressure service. Inconel 725HS was needed for higher pressure service.
Standard testing, serializing, tracking procedures were also implemented.
Stre
ss (
psi)
Strain in/in
17-4 PH in 1075 Cond
Inconel 725
Ti-Beta-C (High STA)
Qualitative Comparison of 4 Materials
MP35N
Ti-Beta-C (Low STA)
kalepatech
Engineering and Design for a Better World
kalepatech
SustainabilityConsulting and Strategy
CRYOGENIC ELECTROMAGNETIC VALVES DESIGN
Thesis Abstract
A major limitation of Gifford-McMahon, G-M, cryocoolers is the requirement to conduction cool the refrigeration load. Earlier attempts to use check valves to rectify oscillating pressure in an external flow loop were unsuccessful. A G-M cryocooler was modified with Boreas style cold electromagnetic valves to utilize oscillating pressure to drive unidirectional flow. Minimum leakage and acceptable electrical dissipation even at 4.5 K was achieved. Preliminary analysis indicated the G-M blow down process could be used to power the flow without degrading cooler capacity.
A paper under the same title was presented at the 11th Annual International Cryocooler Convention in Keystone Colorado. The paper appeared in the Cryocoolers 11 publication in 2001.
Cryocooler
Valve Head
Flexures
Coils
Moving Core
Back Iron
Valve Spring
Spring Washers
Indium Seal
Valve Housing