Heuristic (engineering)
Encyclopedia
In engineering
, heuristics are experience-based methods that are used to reduce the need for calculations pertaining to equipment size, performance, or operating conditions. Heuristics are fallible and they do not guarantee a correct solution. It is important to understand their limitations when applying them to different equipment and processes. Even though heuristics are limited, they may be of value because they offer time saving approximations in preliminary process design.
Problem solving methods are intrinsic to forensic engineering
methods where failures are analysed for the root cause
or causes. Only when failures have been investigated with conclusive results can remedial action be taken with confidence.
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
, heuristics are experience-based methods that are used to reduce the need for calculations pertaining to equipment size, performance, or operating conditions. Heuristics are fallible and they do not guarantee a correct solution. It is important to understand their limitations when applying them to different equipment and processes. Even though heuristics are limited, they may be of value because they offer time saving approximations in preliminary process design.
Problem solving methods are intrinsic to forensic engineering
Forensic engineering
Forensic engineering is the investigation of materials, products, structures or components that fail or do not operate or function as intended, causing personal injury or damage to property. The consequences of failure are dealt with by the law of product liability. The field also deals with...
methods where failures are analysed for the root cause
Root cause
A root cause is rarely an initiating cause of a causal chain which leads to an outcome or effect of interest. Commonly, root cause is misused to describe the depth in the causal chain where an intervention could reasonably be implemented to change performance and prevent an undesirable outcome.In...
or causes. Only when failures have been investigated with conclusive results can remedial action be taken with confidence.
Storage Vessels
These heuristics were taken from Turton's "Analysis, Synthesis, and Design of Chemical Processes".- Use vertical tanks on legs when the tank is less than 3.8 m³.
- Use horizontal tanks on concrete supports when the tank is between 3.8 and 38 m³,
- Use vertical tanks on concrete pads when the tank is beyond 38 m³,
- Liquids subject to breathing losses may be stored in tanks with floating or expansion roofs for conservation.
- Freeboard is 15% below 1.9 m³ and 10% above 1.9 m³.
- Thirty day capacity often is specified for raw materials and products, but depends on connecting transportation equipment schedules.
Pumps
These heuristics were taken from Turton's "Analysis, Synthesis, and Design of Chemical Processes".- Centrifugal pumps: Single Stage: for of 0.057-18.9 m³/min, 152 m maximum head. Multistage: for 0.076-41.6 m³/min, 1675 m maximum head. Efficiency is 45% at 0.378 m³/min, 70% at 1.89 m³/min, 80% at 37.8 m³/min.
- Axial pumps: for 0.076-378 m³/min, 12 m head, 65-85% efficiency.
- Rotary pumps: for 0.00378-18.9 m³/min, 15,200 m head, 50-80% efficiency.
- Reciprocating pumps: for 0.0378-37.8 m³/min, 300 km head maximum. Efficiency is 70% at 7.46 kW, 85% at 37.3 kW, and 90% at 373 kW.
External links
- http://www.aiche.org/uploadedFiles/Students/DepartmentUploads/heuristics.pdf-PDF from AICHE website that shows more heuristics.