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