Pattern-based reasoning for rapid redesign: a proactive approach

Abstract

This paper describes our continued effort in the development of the model-based rapid redesign methodology. In the prior work (Chen et al. in ASME J Mech Des 129:283–294, 2007), we have explored and applied various decomposition patterns for rapid redesign to effectively control design change propagation. Since the decomposition process for redesign is not activated until the presence of a redesign request, this prior work represents a reactive approach where a new set of decomposition patterns should be generated in accordance with a different redesign request input. As an extension to our redesign methodology, this paper presents a proactive approach to complement the existing methodology for rapid redesign. In this approach, the decomposition patterns capturing generic decomposed structures of a given design model are created in advance and stored in a design library before any redesign request emerges. These pre-generated patterns are able to address any upcoming redesign request without further decomposition procedures in redesign. This proactive approach is developed in a new framework of pattern-based reasoning that is built on the mechanism “case → pattern → strategy.” Two methodological components, Proactive Redesign Decomposition and Redesign Condition Analysis, are introduced along with a redesign application to an existing air-cooled condenser for illustration. This redesign approach is particularly useful when it requires only minor yet frequent modifications for the existing design.

Appendix: Description of parameters (columns) and functions (rows) for the example problem

Column / row	Description
C 1	Tube outer diameter (m)
C 2	Tube inner diameter (m)
C 3	Tube pitch (m)
C 4	Tube wall thickness (m)
C 5	Air specific heat (kJ/kgK)
C 6	Air density (kg/m3)
C 7	Air viscosity (Ns/m2)
C 8	Air conductivity (W/m·K)
C 9	Fin material conductivity (W/mK)
C 10	Additive heat resistance due to dust, etc. (m2 K/W)
C 11	Surface condition factor (irregular: 0.11; regular: 0.07)
C 12	Evaporating temperature (°C)
C 13	Outdoor air temperature (°C)
C 14	Leaving air temperature (°C)
C 15	Condensing temperature (refrigerant saturation, °C)
C 16	Logarithm mean temperature between air and refrigerant (°C)
C 17	Vertical portion of total fin and tube area (m2)
C 18	Horizontal portion of total fin and tube area (m2)
C 19	Average area of 1-m long tube surface (m2)
C 20	Total fin and tube area (m2)
C 21	Ratio of A ∑ to tube inner surface area (8 ~ 10)
C 22	Ratio of net flow area to face air area
C 23	Heat transfer area (m2)
C 24	Face air velocity (m/s)
C 25	Net flow area velocity (m/s)
C 26	Efficiency of fin and tube
C 27	Efficiency of fin
C 28	Refrigerant heat transfer coefficient (W/m2 K)
C 29	Air-side heat transfer coefficient (W/m2 K)
C 30	Air-side equivalent heat transfer coefficient (W/m2 K)
C 31	Overall heat transfer conductance (W/m2 K)
C 32	Total length of (fin and) tube (m)
C 33	Total number of tubes
C 34	Length per tube (m)
C 35	Number of tube rows (2 ~ 4)
C 36	Number of tubes per row
C 37	Width of condenser (m)
C 38	Cooling capacity (W)
C 39	Heat rejection load (W)
C 40	Air mass flow rate (kg/s)
C 41	Heat flux (200 ~ 300 W/m2)
C 42	Reynolds number
C 43	Air-side resistance (air pressure drop, Pa)
C 44	Factor related to ϕ k vs. ϕ 0
C 45	Refrigerant thermal property coefficient (W3 N/m6K3 s)
C 46	Exponential factor (variable) for K calculation
C 47	Exponential factor (variable) for K calculation
C 48	Coefficient (variable) related to air flow
C 49	Coefficient (variable) related to fin and tube structure
C 50	Air flow resistance correction coefficient
C 51	Cross-sectional equivalent diameter of air flow (m)
C 52	Dimensionless equivalent fin height (m)
C 53	Fin pitch (m)
C 54	Fin thickness (m)
C 55	Fin height (m)
C 56	Fin length along air flow direction (m)
Row
R 1	Compute heat rejection load for condenser
R 2
R 3
R 4	Select “plate fin with disordered rows of tubes”, and compute the related structural parameters
R 5
R 6
R 7
R 8
R 9
R 10
R 11
R 12
R 13	Compute cool air flow mass flow rate
R 14
R 15	Compute air related velocities
R 16
R 17	Set refrigerant heat transfer coefficient
R 18
R 19	Set air-side equivalent heat transfer coefficient
R 20
R 21
R 22
R 23
R 24
R 25
R 26
R 27
R 28
R 29
R 30
R 31	Set overall heat transfer conductance
R 32
R 33	Compute log-mean temperature
R 34	Find heat flux, and determine heat transfer area
R 35
R 36	Configure condenser structural parameters
R 37
R 38
R 39
R 40	Compute air pressure drop
R 41